12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611711811912012112212312412512612712812913013113213313413513613713813914014114214314414514614714814915015115215315415515615715815916016116216316416516616716816917017117217317417517617717817918018118218318418518618718818919019119219319419519619719819920020120220320420520620720820921021121221321421521621721821922022122222322422522622722822923023123223323423523623723823924024124224324424524624724824925025125225325425525625725825926026126226326426526626726826927027127227327427527627727827928028128228328428528628728828929029129229329429529629729829930030130230330430530630730830931031131231331431531631731831932032132232332432532632732832933033133233333433533633733833934034134234334434534634734834935035135235335435535635735835936036136236336436536636736836937037137237337437537637737837938038138238338438538638738838939039139239339439539639739839940040140240340440540640740840941041141241341441541641741841942042142242342442542642742842943043143243343443543643743843944044144244344444544644744844945045145245345445545645745845946046146246346446546646746846947047147247347447547647747847948048148248348448548648748848949049149249349449549649749849950050150250350450550650750850951051151251351451551651751851952052152252352452552652752852953053153253353453553653753853954054154254354454554654754854955055155255355455555655755855956056156256356456556656756856957057157257357457557657757857958058158258358458558658758858959059159259359459559659759859960060160260360460560660760860961061161261361461561661761861962062162262362462562662762862963063163263363463563663763863964064164264364464564664764864965065165265365465565665765865966066166266366466566666766866967067167267367467567667767867968068168268368468568668768868969069169269369469569669769869970070170270370470570670770870971071171271371471571671771871972072172272372472572672772872973073173273373473573673773873974074174274374474574674774874975075175275375475575675775875976076176276376476576676776876977077177277377477577677777877978078178278378478578678778878979079179279379479579679779879980080180280380480580680780880981081181281381481581681781881982082182282382482582682782882983083183283383483583683783883984084184284384484584684784884985085185285385485585685785885986086186286386486586686786886987087187287387487587687787887988088188288388488588688788888989089189289389489589689789889990090190290390490590690790890991091191291391491591691791891992092192292392492592692792892993093193293393493593693793893994094194294394494594694794894995095195295395495595695795895996096196296396496596696796896997097197297397497597697797897998098198298398498598698798898999099199299399499599699799899910001001100210031004100510061007100810091010101110121013101410151016101710181019102010211022102310241025102610271028102910301031103210331034103510361037103810391040104110421043104410451046104710481049105010511052105310541055105610571058105910601061106210631064106510661067106810691070107110721073107410751076107710781079108010811082108310841085108610871088108910901091109210931094109510961097109810991100110111021103110411051106110711081109111011111112111311141115111611171118111911201121112211231124112511261127112811291130113111321133113411351136113711381139114011411142114311441145114611471148114911501151115211531154115511561157115811591160116111621163116411651166116711681169117011711172117311741175117611771178117911801181118211831184118511861187118811891190119111921193119411951196119711981199120012011202120312041205120612071208120912101211121212131214121512161217121812191220122112221223122412251226122712281229123012311232123312341235123612371238123912401241124212431244124512461247124812491250125112521253125412551256125712581259126012611262126312641265126612671268126912701271127212731274127512761277127812791280128112821283128412851286128712881289129012911292129312941295129612971298129913001301130213031304130513061307130813091310131113121313131413151316131713181319132013211322132313241325132613271328132913301331133213331334133513361337133813391340134113421343134413451346134713481349135013511352135313541355135613571358135913601361136213631364136513661367136813691370137113721373137413751376137713781379138013811382138313841385138613871388138913901391139213931394139513961397139813991400140114021403140414051406140714081409141014111412141314141415141614171418141914201421142214231424142514261427142814291430143114321433143414351436143714381439144014411442144314441445144614471448144914501451145214531454145514561457145814591460146114621463146414651466146714681469147014711472147314741475147614771478147914801481148214831484148514861487148814891490149114921493149414951496149714981499150015011502150315041505150615071508150915101511151215131514151515161517151815191520152115221523152415251526152715281529153015311532153315341535153615371538153915401541154215431544154515461547154815491550155115521553155415551556155715581559156015611562156315641565156615671568156915701571157215731574157515761577157815791580158115821583158415851586158715881589159015911592159315941595159615971598159916001601160216031604160516061607160816091610161116121613161416151616161716181619162016211622162316241625162616271628162916301631163216331634163516361637163816391640164116421643164416451646164716481649165016511652165316541655165616571658165916601661166216631664166516661667166816691670167116721673167416751676167716781679168016811682168316841685168616871688168916901691169216931694169516961697169816991700170117021703170417051706170717081709171017111712171317141715171617171718171917201721172217231724172517261727172817291730173117321733173417351736173717381739174017411742174317441745174617471748174917501751175217531754175517561757175817591760176117621763176417651766176717681769177017711772177317741775177617771778177917801781178217831784178517861787178817891790179117921793179417951796179717981799180018011802180318041805180618071808180918101811181218131814181518161817181818191820182118221823182418251826182718281829183018311832183318341835183618371838183918401841184218431844184518461847184818491850185118521853185418551856185718581859186018611862186318641865186618671868186918701871187218731874187518761877187818791880188118821883188418851886188718881889189018911892189318941895189618971898189919001901190219031904190519061907190819091910191119121913191419151916191719181919192019211922192319241925192619271928192919301931193219331934193519361937193819391940194119421943194419451946194719481949195019511952195319541955195619571958195919601961196219631964196519661967196819691970197119721973197419751976197719781979198019811982198319841985198619871988198919901991199219931994199519961997199819992000200120022003200420052006200720082009201020112012201320142015201620172018201920202021202220232024202520262027202820292030203120322033203420352036203720382039204020412042204320442045204620472048204920502051205220532054205520562057205820592060206120622063206420652066206720682069207020712072207320742075207620772078207920802081208220832084208520862087208820892090209120922093209420952096209720982099210021012102210321042105210621072108210921102111211221132114211521162117211821192120212121222123212421252126212721282129213021312132213321342135213621372138213921402141214221432144214521462147214821492150215121522153215421552156215721582159216021612162216321642165216621672168216921702171217221732174217521762177217821792180218121822183218421852186218721882189219021912192219321942195219621972198219922002201220222032204220522062207220822092210221122122213221422152216221722182219222022212222222322242225222622272228222922302231223222332234223522362237223822392240224122422243224422452246224722482249225022512252225322542255225622572258225922602261226222632264226522662267226822692270227122722273227422752276227722782279228022812282228322842285228622872288228922902291229222932294229522962297229822992300230123022303230423052306230723082309231023112312231323142315231623172318231923202321232223232324232523262327232823292330233123322333233423352336233723382339234023412342234323442345234623472348234923502351235223532354235523562357235823592360236123622363236423652366236723682369237023712372237323742375237623772378237923802381238223832384238523862387238823892390239123922393239423952396239723982399240024012402240324042405240624072408240924102411241224132414241524162417241824192420242124222423242424252426242724282429243024312432243324342435243624372438243924402441244224432444244524462447244824492450245124522453245424552456245724582459246024612462246324642465246624672468246924702471247224732474247524762477247824792480248124822483248424852486248724882489249024912492249324942495249624972498249925002501250225032504250525062507250825092510251125122513251425152516251725182519252025212522252325242525252625272528252925302531253225332534253525362537253825392540254125422543254425452546254725482549255025512552255325542555255625572558255925602561256225632564256525662567256825692570257125722573257425752576257725782579258025812582258325842585258625872588258925902591259225932594259525962597259825992600260126022603260426052606260726082609261026112612261326142615261626172618261926202621262226232624262526262627262826292630263126322633263426352636263726382639264026412642264326442645264626472648264926502651265226532654265526562657265826592660266126622663266426652666266726682669267026712672267326742675267626772678267926802681268226832684268526862687268826892690269126922693269426952696269726982699270027012702270327042705270627072708270927102711271227132714271527162717271827192720272127222723272427252726272727282729273027312732273327342735273627372738273927402741274227432744274527462747274827492750275127522753275427552756275727582759276027612762276327642765276627672768276927702771277227732774277527762777277827792780278127822783278427852786278727882789279027912792279327942795279627972798279928002801280228032804280528062807280828092810281128122813281428152816281728182819282028212822282328242825282628272828282928302831283228332834283528362837283828392840284128422843284428452846284728482849285028512852285328542855285628572858285928602861286228632864286528662867286828692870287128722873287428752876287728782879288028812882288328842885288628872888288928902891289228932894289528962897289828992900290129022903290429052906290729082909291029112912291329142915291629172918291929202921292229232924292529262927292829292930293129322933293429352936293729382939294029412942294329442945294629472948294929502951295229532954295529562957295829592960296129622963296429652966296729682969297029712972297329742975297629772978297929802981298229832984298529862987298829892990299129922993299429952996299729982999300030013002300330043005300630073008300930103011301230133014301530163017301830193020302130223023302430253026302730283029303030313032303330343035303630373038303930403041304230433044304530463047304830493050305130523053305430553056305730583059306030613062306330643065306630673068306930703071307230733074307530763077307830793080308130823083308430853086308730883089309030913092309330943095309630973098309931003101310231033104310531063107310831093110311131123113311431153116311731183119312031213122312331243125312631273128312931303131313231333134313531363137313831393140314131423143314431453146314731483149315031513152315331543155315631573158315931603161316231633164316531663167316831693170317131723173317431753176317731783179318031813182318331843185318631873188318931903191319231933194319531963197319831993200320132023203320432053206320732083209321032113212321332143215321632173218321932203221322232233224322532263227322832293230323132323233323432353236323732383239324032413242324332443245324632473248324932503251325232533254325532563257325832593260326132623263326432653266326732683269327032713272327332743275327632773278327932803281328232833284328532863287328832893290329132923293329432953296329732983299330033013302330333043305330633073308330933103311331233133314331533163317331833193320332133223323332433253326332733283329333033313332333333343335333633373338333933403341334233433344334533463347334833493350335133523353335433553356335733583359336033613362336333643365336633673368336933703371337233733374337533763377337833793380338133823383338433853386338733883389339033913392339333943395339633973398339934003401340234033404340534063407340834093410341134123413341434153416341734183419342034213422342334243425342634273428342934303431343234333434343534363437343834393440344134423443344434453446344734483449345034513452345334543455345634573458345934603461346234633464346534663467346834693470347134723473347434753476347734783479348034813482348334843485348634873488348934903491349234933494349534963497349834993500350135023503350435053506350735083509351035113512351335143515351635173518351935203521352235233524352535263527352835293530353135323533353435353536353735383539354035413542354335443545354635473548354935503551355235533554355535563557355835593560356135623563356435653566356735683569357035713572357335743575357635773578357935803581358235833584358535863587358835893590359135923593359435953596359735983599360036013602360336043605360636073608360936103611361236133614361536163617361836193620362136223623362436253626362736283629363036313632363336343635363636373638363936403641364236433644364536463647364836493650365136523653365436553656365736583659366036613662366336643665366636673668366936703671367236733674367536763677367836793680368136823683368436853686368736883689369036913692369336943695369636973698369937003701370237033704370537063707370837093710371137123713371437153716371737183719372037213722372337243725372637273728372937303731373237333734373537363737373837393740374137423743374437453746374737483749375037513752375337543755375637573758375937603761376237633764376537663767376837693770377137723773377437753776377737783779378037813782378337843785378637873788378937903791379237933794379537963797379837993800380138023803380438053806380738083809381038113812381338143815381638173818381938203821382238233824382538263827382838293830383138323833383438353836383738383839384038413842384338443845384638473848384938503851385238533854385538563857385838593860386138623863386438653866386738683869387038713872387338743875387638773878387938803881388238833884388538863887388838893890389138923893389438953896389738983899390039013902390339043905390639073908390939103911391239133914391539163917391839193920392139223923392439253926392739283929393039313932393339343935393639373938393939403941394239433944394539463947394839493950395139523953395439553956395739583959396039613962396339643965396639673968396939703971397239733974397539763977397839793980398139823983398439853986398739883989399039913992399339943995399639973998399940004001400240034004400540064007400840094010401140124013401440154016401740184019402040214022402340244025402640274028402940304031403240334034403540364037403840394040404140424043404440454046404740484049405040514052405340544055405640574058405940604061406240634064406540664067406840694070407140724073407440754076407740784079408040814082408340844085408640874088408940904091409240934094409540964097409840994100410141024103410441054106410741084109411041114112411341144115411641174118411941204121412241234124412541264127412841294130413141324133413441354136413741384139414041414142414341444145414641474148414941504151415241534154415541564157415841594160416141624163416441654166416741684169417041714172417341744175417641774178417941804181418241834184418541864187418841894190419141924193419441954196419741984199420042014202420342044205420642074208420942104211421242134214421542164217421842194220422142224223422442254226422742284229423042314232423342344235423642374238423942404241424242434244424542464247424842494250425142524253425442554256425742584259426042614262426342644265426642674268426942704271427242734274427542764277427842794280428142824283428442854286428742884289429042914292429342944295429642974298429943004301430243034304430543064307430843094310431143124313431443154316431743184319432043214322432343244325432643274328432943304331433243334334433543364337433843394340434143424343434443454346434743484349435043514352435343544355435643574358435943604361436243634364436543664367436843694370437143724373437443754376437743784379438043814382438343844385438643874388438943904391439243934394439543964397439843994400440144024403440444054406440744084409441044114412441344144415441644174418441944204421442244234424442544264427442844294430443144324433443444354436443744384439444044414442444344444445444644474448444944504451445244534454445544564457445844594460446144624463446444654466446744684469447044714472447344744475447644774478447944804481448244834484448544864487448844894490449144924493449444954496449744984499450045014502450345044505450645074508450945104511451245134514451545164517451845194520452145224523452445254526452745284529453045314532453345344535453645374538453945404541454245434544454545464547454845494550455145524553455445554556455745584559456045614562456345644565456645674568456945704571457245734574457545764577457845794580458145824583458445854586458745884589459045914592459345944595459645974598459946004601460246034604460546064607460846094610461146124613461446154616461746184619462046214622462346244625462646274628462946304631463246334634463546364637463846394640464146424643464446454646464746484649465046514652465346544655465646574658465946604661466246634664466546664667466846694670467146724673467446754676467746784679468046814682468346844685468646874688468946904691469246934694469546964697469846994700470147024703470447054706470747084709471047114712471347144715471647174718471947204721472247234724472547264727472847294730473147324733473447354736473747384739474047414742474347444745474647474748474947504751475247534754475547564757475847594760476147624763476447654766476747684769477047714772477347744775477647774778477947804781478247834784478547864787478847894790479147924793479447954796479747984799480048014802480348044805480648074808480948104811481248134814481548164817481848194820482148224823482448254826482748284829483048314832483348344835483648374838483948404841484248434844484548464847484848494850485148524853485448554856485748584859486048614862486348644865486648674868486948704871487248734874487548764877 |
- /*
- ** 2001 September 15
- **
- ** The author disclaims copyright to this source code. In place of
- ** a legal notice, here is a blessing:
- **
- ** May you do good and not evil.
- ** May you find forgiveness for yourself and forgive others.
- ** May you share freely, never taking more than you give.
- **
- *************************************************************************
- ** This file contains C code routines that are called by the parser
- ** to handle SELECT statements in SQLite.
- */
- #include "sqliteInt.h"
- /*
- ** Delete all the content of a Select structure but do not deallocate
- ** the select structure itself.
- */
- static void clearSelect(sqlite3 *db, Select *p){
- sqlite3ExprListDelete(db, p->pEList);
- sqlite3SrcListDelete(db, p->pSrc);
- sqlite3ExprDelete(db, p->pWhere);
- sqlite3ExprListDelete(db, p->pGroupBy);
- sqlite3ExprDelete(db, p->pHaving);
- sqlite3ExprListDelete(db, p->pOrderBy);
- sqlite3SelectDelete(db, p->pPrior);
- sqlite3ExprDelete(db, p->pLimit);
- sqlite3ExprDelete(db, p->pOffset);
- }
- /*
- ** Initialize a SelectDest structure.
- */
- void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
- pDest->eDest = (u8)eDest;
- pDest->iSDParm = iParm;
- pDest->affSdst = 0;
- pDest->iSdst = 0;
- pDest->nSdst = 0;
- }
- /*
- ** Allocate a new Select structure and return a pointer to that
- ** structure.
- */
- Select *sqlite3SelectNew(
- Parse *pParse, /* Parsing context */
- ExprList *pEList, /* which columns to include in the result */
- SrcList *pSrc, /* the FROM clause -- which tables to scan */
- Expr *pWhere, /* the WHERE clause */
- ExprList *pGroupBy, /* the GROUP BY clause */
- Expr *pHaving, /* the HAVING clause */
- ExprList *pOrderBy, /* the ORDER BY clause */
- u16 selFlags, /* Flag parameters, such as SF_Distinct */
- Expr *pLimit, /* LIMIT value. NULL means not used */
- Expr *pOffset /* OFFSET value. NULL means no offset */
- ){
- Select *pNew;
- Select standin;
- sqlite3 *db = pParse->db;
- pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
- assert( db->mallocFailed || !pOffset || pLimit ); /* OFFSET implies LIMIT */
- if( pNew==0 ){
- assert( db->mallocFailed );
- pNew = &standin;
- memset(pNew, 0, sizeof(*pNew));
- }
- if( pEList==0 ){
- pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0));
- }
- pNew->pEList = pEList;
- if( pSrc==0 ) pSrc = sqlite3DbMallocZero(db, sizeof(*pSrc));
- pNew->pSrc = pSrc;
- pNew->pWhere = pWhere;
- pNew->pGroupBy = pGroupBy;
- pNew->pHaving = pHaving;
- pNew->pOrderBy = pOrderBy;
- pNew->selFlags = selFlags;
- pNew->op = TK_SELECT;
- pNew->pLimit = pLimit;
- pNew->pOffset = pOffset;
- assert( pOffset==0 || pLimit!=0 );
- pNew->addrOpenEphm[0] = -1;
- pNew->addrOpenEphm[1] = -1;
- pNew->addrOpenEphm[2] = -1;
- if( db->mallocFailed ) {
- clearSelect(db, pNew);
- if( pNew!=&standin ) sqlite3DbFree(db, pNew);
- pNew = 0;
- }else{
- assert( pNew->pSrc!=0 || pParse->nErr>0 );
- }
- assert( pNew!=&standin );
- return pNew;
- }
- /*
- ** Delete the given Select structure and all of its substructures.
- */
- void sqlite3SelectDelete(sqlite3 *db, Select *p){
- if( p ){
- clearSelect(db, p);
- sqlite3DbFree(db, p);
- }
- }
- /*
- ** Given 1 to 3 identifiers preceding the JOIN keyword, determine the
- ** type of join. Return an integer constant that expresses that type
- ** in terms of the following bit values:
- **
- ** JT_INNER
- ** JT_CROSS
- ** JT_OUTER
- ** JT_NATURAL
- ** JT_LEFT
- ** JT_RIGHT
- **
- ** A full outer join is the combination of JT_LEFT and JT_RIGHT.
- **
- ** If an illegal or unsupported join type is seen, then still return
- ** a join type, but put an error in the pParse structure.
- */
- int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
- int jointype = 0;
- Token *apAll[3];
- Token *p;
- /* 0123456789 123456789 123456789 123 */
- static const char zKeyText[] = "naturaleftouterightfullinnercross";
- static const struct {
- u8 i; /* Beginning of keyword text in zKeyText[] */
- u8 nChar; /* Length of the keyword in characters */
- u8 code; /* Join type mask */
- } aKeyword[] = {
- /* natural */ { 0, 7, JT_NATURAL },
- /* left */ { 6, 4, JT_LEFT|JT_OUTER },
- /* outer */ { 10, 5, JT_OUTER },
- /* right */ { 14, 5, JT_RIGHT|JT_OUTER },
- /* full */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
- /* inner */ { 23, 5, JT_INNER },
- /* cross */ { 28, 5, JT_INNER|JT_CROSS },
- };
- int i, j;
- apAll[0] = pA;
- apAll[1] = pB;
- apAll[2] = pC;
- for(i=0; i<3 && apAll[i]; i++){
- p = apAll[i];
- for(j=0; j<ArraySize(aKeyword); j++){
- if( p->n==aKeyword[j].nChar
- && sqlite3StrNICmp((char*)p->z, &zKeyText[aKeyword[j].i], p->n)==0 ){
- jointype |= aKeyword[j].code;
- break;
- }
- }
- testcase( j==0 || j==1 || j==2 || j==3 || j==4 || j==5 || j==6 );
- if( j>=ArraySize(aKeyword) ){
- jointype |= JT_ERROR;
- break;
- }
- }
- if(
- (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
- (jointype & JT_ERROR)!=0
- ){
- const char *zSp = " ";
- assert( pB!=0 );
- if( pC==0 ){ zSp++; }
- sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
- "%T %T%s%T", pA, pB, zSp, pC);
- jointype = JT_INNER;
- }else if( (jointype & JT_OUTER)!=0
- && (jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ){
- sqlite3ErrorMsg(pParse,
- "RIGHT and FULL OUTER JOINs are not currently supported");
- jointype = JT_INNER;
- }
- return jointype;
- }
- /*
- ** Return the index of a column in a table. Return -1 if the column
- ** is not contained in the table.
- */
- static int columnIndex(Table *pTab, const char *zCol){
- int i;
- for(i=0; i<pTab->nCol; i++){
- if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
- }
- return -1;
- }
- /*
- ** Search the first N tables in pSrc, from left to right, looking for a
- ** table that has a column named zCol.
- **
- ** When found, set *piTab and *piCol to the table index and column index
- ** of the matching column and return TRUE.
- **
- ** If not found, return FALSE.
- */
- static int tableAndColumnIndex(
- SrcList *pSrc, /* Array of tables to search */
- int N, /* Number of tables in pSrc->a[] to search */
- const char *zCol, /* Name of the column we are looking for */
- int *piTab, /* Write index of pSrc->a[] here */
- int *piCol /* Write index of pSrc->a[*piTab].pTab->aCol[] here */
- ){
- int i; /* For looping over tables in pSrc */
- int iCol; /* Index of column matching zCol */
- assert( (piTab==0)==(piCol==0) ); /* Both or neither are NULL */
- for(i=0; i<N; i++){
- iCol = columnIndex(pSrc->a[i].pTab, zCol);
- if( iCol>=0 ){
- if( piTab ){
- *piTab = i;
- *piCol = iCol;
- }
- return 1;
- }
- }
- return 0;
- }
- /*
- ** This function is used to add terms implied by JOIN syntax to the
- ** WHERE clause expression of a SELECT statement. The new term, which
- ** is ANDed with the existing WHERE clause, is of the form:
- **
- ** (tab1.col1 = tab2.col2)
- **
- ** where tab1 is the iSrc'th table in SrcList pSrc and tab2 is the
- ** (iSrc+1)'th. Column col1 is column iColLeft of tab1, and col2 is
- ** column iColRight of tab2.
- */
- static void addWhereTerm(
- Parse *pParse, /* Parsing context */
- SrcList *pSrc, /* List of tables in FROM clause */
- int iLeft, /* Index of first table to join in pSrc */
- int iColLeft, /* Index of column in first table */
- int iRight, /* Index of second table in pSrc */
- int iColRight, /* Index of column in second table */
- int isOuterJoin, /* True if this is an OUTER join */
- Expr **ppWhere /* IN/OUT: The WHERE clause to add to */
- ){
- sqlite3 *db = pParse->db;
- Expr *pE1;
- Expr *pE2;
- Expr *pEq;
- assert( iLeft<iRight );
- assert( pSrc->nSrc>iRight );
- assert( pSrc->a[iLeft].pTab );
- assert( pSrc->a[iRight].pTab );
- pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iColLeft);
- pE2 = sqlite3CreateColumnExpr(db, pSrc, iRight, iColRight);
- pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2, 0);
- if( pEq && isOuterJoin ){
- ExprSetProperty(pEq, EP_FromJoin);
- assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) );
- ExprSetVVAProperty(pEq, EP_NoReduce);
- pEq->iRightJoinTable = (i16)pE2->iTable;
- }
- *ppWhere = sqlite3ExprAnd(db, *ppWhere, pEq);
- }
- /*
- ** Set the EP_FromJoin property on all terms of the given expression.
- ** And set the Expr.iRightJoinTable to iTable for every term in the
- ** expression.
- **
- ** The EP_FromJoin property is used on terms of an expression to tell
- ** the LEFT OUTER JOIN processing logic that this term is part of the
- ** join restriction specified in the ON or USING clause and not a part
- ** of the more general WHERE clause. These terms are moved over to the
- ** WHERE clause during join processing but we need to remember that they
- ** originated in the ON or USING clause.
- **
- ** The Expr.iRightJoinTable tells the WHERE clause processing that the
- ** expression depends on table iRightJoinTable even if that table is not
- ** explicitly mentioned in the expression. That information is needed
- ** for cases like this:
- **
- ** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
- **
- ** The where clause needs to defer the handling of the t1.x=5
- ** term until after the t2 loop of the join. In that way, a
- ** NULL t2 row will be inserted whenever t1.x!=5. If we do not
- ** defer the handling of t1.x=5, it will be processed immediately
- ** after the t1 loop and rows with t1.x!=5 will never appear in
- ** the output, which is incorrect.
- */
- static void setJoinExpr(Expr *p, int iTable){
- while( p ){
- ExprSetProperty(p, EP_FromJoin);
- assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
- ExprSetVVAProperty(p, EP_NoReduce);
- p->iRightJoinTable = (i16)iTable;
- setJoinExpr(p->pLeft, iTable);
- p = p->pRight;
- }
- }
- /*
- ** This routine processes the join information for a SELECT statement.
- ** ON and USING clauses are converted into extra terms of the WHERE clause.
- ** NATURAL joins also create extra WHERE clause terms.
- **
- ** The terms of a FROM clause are contained in the Select.pSrc structure.
- ** The left most table is the first entry in Select.pSrc. The right-most
- ** table is the last entry. The join operator is held in the entry to
- ** the left. Thus entry 0 contains the join operator for the join between
- ** entries 0 and 1. Any ON or USING clauses associated with the join are
- ** also attached to the left entry.
- **
- ** This routine returns the number of errors encountered.
- */
- static int sqliteProcessJoin(Parse *pParse, Select *p){
- SrcList *pSrc; /* All tables in the FROM clause */
- int i, j; /* Loop counters */
- struct SrcList_item *pLeft; /* Left table being joined */
- struct SrcList_item *pRight; /* Right table being joined */
- pSrc = p->pSrc;
- pLeft = &pSrc->a[0];
- pRight = &pLeft[1];
- for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
- Table *pLeftTab = pLeft->pTab;
- Table *pRightTab = pRight->pTab;
- int isOuter;
- if( NEVER(pLeftTab==0 || pRightTab==0) ) continue;
- isOuter = (pRight->jointype & JT_OUTER)!=0;
- /* When the NATURAL keyword is present, add WHERE clause terms for
- ** every column that the two tables have in common.
- */
- if( pRight->jointype & JT_NATURAL ){
- if( pRight->pOn || pRight->pUsing ){
- sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
- "an ON or USING clause", 0);
- return 1;
- }
- for(j=0; j<pRightTab->nCol; j++){
- char *zName; /* Name of column in the right table */
- int iLeft; /* Matching left table */
- int iLeftCol; /* Matching column in the left table */
- zName = pRightTab->aCol[j].zName;
- if( tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol) ){
- addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, j,
- isOuter, &p->pWhere);
- }
- }
- }
- /* Disallow both ON and USING clauses in the same join
- */
- if( pRight->pOn && pRight->pUsing ){
- sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
- "clauses in the same join");
- return 1;
- }
- /* Add the ON clause to the end of the WHERE clause, connected by
- ** an AND operator.
- */
- if( pRight->pOn ){
- if( isOuter ) setJoinExpr(pRight->pOn, pRight->iCursor);
- p->pWhere = sqlite3ExprAnd(pParse->db, p->pWhere, pRight->pOn);
- pRight->pOn = 0;
- }
- /* Create extra terms on the WHERE clause for each column named
- ** in the USING clause. Example: If the two tables to be joined are
- ** A and B and the USING clause names X, Y, and Z, then add this
- ** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
- ** Report an error if any column mentioned in the USING clause is
- ** not contained in both tables to be joined.
- */
- if( pRight->pUsing ){
- IdList *pList = pRight->pUsing;
- for(j=0; j<pList->nId; j++){
- char *zName; /* Name of the term in the USING clause */
- int iLeft; /* Table on the left with matching column name */
- int iLeftCol; /* Column number of matching column on the left */
- int iRightCol; /* Column number of matching column on the right */
- zName = pList->a[j].zName;
- iRightCol = columnIndex(pRightTab, zName);
- if( iRightCol<0
- || !tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol)
- ){
- sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
- "not present in both tables", zName);
- return 1;
- }
- addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, iRightCol,
- isOuter, &p->pWhere);
- }
- }
- }
- return 0;
- }
- /*
- ** Insert code into "v" that will push the record on the top of the
- ** stack into the sorter.
- */
- static void pushOntoSorter(
- Parse *pParse, /* Parser context */
- ExprList *pOrderBy, /* The ORDER BY clause */
- Select *pSelect, /* The whole SELECT statement */
- int regData /* Register holding data to be sorted */
- ){
- Vdbe *v = pParse->pVdbe;
- int nExpr = pOrderBy->nExpr;
- int regBase = sqlite3GetTempRange(pParse, nExpr+2);
- int regRecord = sqlite3GetTempReg(pParse);
- int op;
- sqlite3ExprCacheClear(pParse);
- sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
- sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
- sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
- sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
- if( pSelect->selFlags & SF_UseSorter ){
- op = OP_SorterInsert;
- }else{
- op = OP_IdxInsert;
- }
- sqlite3VdbeAddOp2(v, op, pOrderBy->iECursor, regRecord);
- sqlite3ReleaseTempReg(pParse, regRecord);
- sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
- if( pSelect->iLimit ){
- int addr1, addr2;
- int iLimit;
- if( pSelect->iOffset ){
- iLimit = pSelect->iOffset+1;
- }else{
- iLimit = pSelect->iLimit;
- }
- addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit);
- sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
- addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
- sqlite3VdbeJumpHere(v, addr1);
- sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
- sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
- sqlite3VdbeJumpHere(v, addr2);
- }
- }
- /*
- ** Add code to implement the OFFSET
- */
- static void codeOffset(
- Vdbe *v, /* Generate code into this VM */
- Select *p, /* The SELECT statement being coded */
- int iContinue /* Jump here to skip the current record */
- ){
- if( p->iOffset && iContinue!=0 ){
- int addr;
- sqlite3VdbeAddOp2(v, OP_AddImm, p->iOffset, -1);
- addr = sqlite3VdbeAddOp1(v, OP_IfNeg, p->iOffset);
- sqlite3VdbeAddOp2(v, OP_Goto, 0, iContinue);
- VdbeComment((v, "skip OFFSET records"));
- sqlite3VdbeJumpHere(v, addr);
- }
- }
- /*
- ** Add code that will check to make sure the N registers starting at iMem
- ** form a distinct entry. iTab is a sorting index that holds previously
- ** seen combinations of the N values. A new entry is made in iTab
- ** if the current N values are new.
- **
- ** A jump to addrRepeat is made and the N+1 values are popped from the
- ** stack if the top N elements are not distinct.
- */
- static void codeDistinct(
- Parse *pParse, /* Parsing and code generating context */
- int iTab, /* A sorting index used to test for distinctness */
- int addrRepeat, /* Jump to here if not distinct */
- int N, /* Number of elements */
- int iMem /* First element */
- ){
- Vdbe *v;
- int r1;
- v = pParse->pVdbe;
- r1 = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, iMem, N);
- sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
- sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
- sqlite3ReleaseTempReg(pParse, r1);
- }
- #ifndef SQLITE_OMIT_SUBQUERY
- /*
- ** Generate an error message when a SELECT is used within a subexpression
- ** (example: "a IN (SELECT * FROM table)") but it has more than 1 result
- ** column. We do this in a subroutine because the error used to occur
- ** in multiple places. (The error only occurs in one place now, but we
- ** retain the subroutine to minimize code disruption.)
- */
- static int checkForMultiColumnSelectError(
- Parse *pParse, /* Parse context. */
- SelectDest *pDest, /* Destination of SELECT results */
- int nExpr /* Number of result columns returned by SELECT */
- ){
- int eDest = pDest->eDest;
- if( nExpr>1 && (eDest==SRT_Mem || eDest==SRT_Set) ){
- sqlite3ErrorMsg(pParse, "only a single result allowed for "
- "a SELECT that is part of an expression");
- return 1;
- }else{
- return 0;
- }
- }
- #endif
- /*
- ** An instance of the following object is used to record information about
- ** how to process the DISTINCT keyword, to simplify passing that information
- ** into the selectInnerLoop() routine.
- */
- typedef struct DistinctCtx DistinctCtx;
- struct DistinctCtx {
- u8 isTnct; /* True if the DISTINCT keyword is present */
- u8 eTnctType; /* One of the WHERE_DISTINCT_* operators */
- int tabTnct; /* Ephemeral table used for DISTINCT processing */
- int addrTnct; /* Address of OP_OpenEphemeral opcode for tabTnct */
- };
- /*
- ** This routine generates the code for the inside of the inner loop
- ** of a SELECT.
- **
- ** If srcTab and nColumn are both zero, then the pEList expressions
- ** are evaluated in order to get the data for this row. If nColumn>0
- ** then data is pulled from srcTab and pEList is used only to get the
- ** datatypes for each column.
- */
- static void selectInnerLoop(
- Parse *pParse, /* The parser context */
- Select *p, /* The complete select statement being coded */
- ExprList *pEList, /* List of values being extracted */
- int srcTab, /* Pull data from this table */
- int nColumn, /* Number of columns in the source table */
- ExprList *pOrderBy, /* If not NULL, sort results using this key */
- DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */
- SelectDest *pDest, /* How to dispose of the results */
- int iContinue, /* Jump here to continue with next row */
- int iBreak /* Jump here to break out of the inner loop */
- ){
- Vdbe *v = pParse->pVdbe;
- int i;
- int hasDistinct; /* True if the DISTINCT keyword is present */
- int regResult; /* Start of memory holding result set */
- int eDest = pDest->eDest; /* How to dispose of results */
- int iParm = pDest->iSDParm; /* First argument to disposal method */
- int nResultCol; /* Number of result columns */
- assert( v );
- if( NEVER(v==0) ) return;
- assert( pEList!=0 );
- hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP;
- if( pOrderBy==0 && !hasDistinct ){
- codeOffset(v, p, iContinue);
- }
- /* Pull the requested columns.
- */
- if( nColumn>0 ){
- nResultCol = nColumn;
- }else{
- nResultCol = pEList->nExpr;
- }
- if( pDest->iSdst==0 ){
- pDest->iSdst = pParse->nMem+1;
- pDest->nSdst = nResultCol;
- pParse->nMem += nResultCol;
- }else{
- assert( pDest->nSdst==nResultCol );
- }
- regResult = pDest->iSdst;
- if( nColumn>0 ){
- for(i=0; i<nColumn; i++){
- sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
- }
- }else if( eDest!=SRT_Exists ){
- /* If the destination is an EXISTS(...) expression, the actual
- ** values returned by the SELECT are not required.
- */
- sqlite3ExprCacheClear(pParse);
- sqlite3ExprCodeExprList(pParse, pEList, regResult, eDest==SRT_Output);
- }
- nColumn = nResultCol;
- /* If the DISTINCT keyword was present on the SELECT statement
- ** and this row has been seen before, then do not make this row
- ** part of the result.
- */
- if( hasDistinct ){
- assert( pEList!=0 );
- assert( pEList->nExpr==nColumn );
- switch( pDistinct->eTnctType ){
- case WHERE_DISTINCT_ORDERED: {
- VdbeOp *pOp; /* No longer required OpenEphemeral instr. */
- int iJump; /* Jump destination */
- int regPrev; /* Previous row content */
- /* Allocate space for the previous row */
- regPrev = pParse->nMem+1;
- pParse->nMem += nColumn;
- /* Change the OP_OpenEphemeral coded earlier to an OP_Null
- ** sets the MEM_Cleared bit on the first register of the
- ** previous value. This will cause the OP_Ne below to always
- ** fail on the first iteration of the loop even if the first
- ** row is all NULLs.
- */
- sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct);
- pOp = sqlite3VdbeGetOp(v, pDistinct->addrTnct);
- pOp->opcode = OP_Null;
- pOp->p1 = 1;
- pOp->p2 = regPrev;
- iJump = sqlite3VdbeCurrentAddr(v) + nColumn;
- for(i=0; i<nColumn; i++){
- CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[i].pExpr);
- if( i<nColumn-1 ){
- sqlite3VdbeAddOp3(v, OP_Ne, regResult+i, iJump, regPrev+i);
- }else{
- sqlite3VdbeAddOp3(v, OP_Eq, regResult+i, iContinue, regPrev+i);
- }
- sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
- sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
- }
- assert( sqlite3VdbeCurrentAddr(v)==iJump );
- sqlite3VdbeAddOp3(v, OP_Copy, regResult, regPrev, nColumn-1);
- break;
- }
- case WHERE_DISTINCT_UNIQUE: {
- sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct);
- break;
- }
- default: {
- assert( pDistinct->eTnctType==WHERE_DISTINCT_UNORDERED );
- codeDistinct(pParse, pDistinct->tabTnct, iContinue, nColumn, regResult);
- break;
- }
- }
- if( pOrderBy==0 ){
- codeOffset(v, p, iContinue);
- }
- }
- switch( eDest ){
- /* In this mode, write each query result to the key of the temporary
- ** table iParm.
- */
- #ifndef SQLITE_OMIT_COMPOUND_SELECT
- case SRT_Union: {
- int r1;
- r1 = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
- sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
- sqlite3ReleaseTempReg(pParse, r1);
- break;
- }
- /* Construct a record from the query result, but instead of
- ** saving that record, use it as a key to delete elements from
- ** the temporary table iParm.
- */
- case SRT_Except: {
- sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nColumn);
- break;
- }
- #endif
- /* Store the result as data using a unique key.
- */
- case SRT_Table:
- case SRT_EphemTab: {
- int r1 = sqlite3GetTempReg(pParse);
- testcase( eDest==SRT_Table );
- testcase( eDest==SRT_EphemTab );
- sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
- if( pOrderBy ){
- pushOntoSorter(pParse, pOrderBy, p, r1);
- }else{
- int r2 = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
- sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
- sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
- sqlite3ReleaseTempReg(pParse, r2);
- }
- sqlite3ReleaseTempReg(pParse, r1);
- break;
- }
- #ifndef SQLITE_OMIT_SUBQUERY
- /* If we are creating a set for an "expr IN (SELECT ...)" construct,
- ** then there should be a single item on the stack. Write this
- ** item into the set table with bogus data.
- */
- case SRT_Set: {
- assert( nColumn==1 );
- pDest->affSdst =
- sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affSdst);
- if( pOrderBy ){
- /* At first glance you would think we could optimize out the
- ** ORDER BY in this case since the order of entries in the set
- ** does not matter. But there might be a LIMIT clause, in which
- ** case the order does matter */
- pushOntoSorter(pParse, pOrderBy, p, regResult);
- }else{
- int r1 = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult,1,r1, &pDest->affSdst, 1);
- sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
- sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
- sqlite3ReleaseTempReg(pParse, r1);
- }
- break;
- }
- /* If any row exist in the result set, record that fact and abort.
- */
- case SRT_Exists: {
- sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
- /* The LIMIT clause will terminate the loop for us */
- break;
- }
- /* If this is a scalar select that is part of an expression, then
- ** store the results in the appropriate memory cell and break out
- ** of the scan loop.
- */
- case SRT_Mem: {
- assert( nColumn==1 );
- if( pOrderBy ){
- pushOntoSorter(pParse, pOrderBy, p, regResult);
- }else{
- sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
- /* The LIMIT clause will jump out of the loop for us */
- }
- break;
- }
- #endif /* #ifndef SQLITE_OMIT_SUBQUERY */
- /* Send the data to the callback function or to a subroutine. In the
- ** case of a subroutine, the subroutine itself is responsible for
- ** popping the data from the stack.
- */
- case SRT_Coroutine:
- case SRT_Output: {
- testcase( eDest==SRT_Coroutine );
- testcase( eDest==SRT_Output );
- if( pOrderBy ){
- int r1 = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
- pushOntoSorter(pParse, pOrderBy, p, r1);
- sqlite3ReleaseTempReg(pParse, r1);
- }else if( eDest==SRT_Coroutine ){
- sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
- }else{
- sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
- sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
- }
- break;
- }
- #if !defined(SQLITE_OMIT_TRIGGER)
- /* Discard the results. This is used for SELECT statements inside
- ** the body of a TRIGGER. The purpose of such selects is to call
- ** user-defined functions that have side effects. We do not care
- ** about the actual results of the select.
- */
- default: {
- assert( eDest==SRT_Discard );
- break;
- }
- #endif
- }
- /* Jump to the end of the loop if the LIMIT is reached. Except, if
- ** there is a sorter, in which case the sorter has already limited
- ** the output for us.
- */
- if( pOrderBy==0 && p->iLimit ){
- sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
- }
- }
- /*
- ** Allocate a KeyInfo object sufficient for an index of N columns.
- **
- ** Actually, always allocate one extra column for the rowid at the end
- ** of the index. So the KeyInfo returned will have space sufficient for
- ** N+1 columns.
- */
- KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N){
- KeyInfo *p = sqlite3DbMallocZero(db,
- sizeof(KeyInfo) + (N+1)*(sizeof(CollSeq*)+1));
- if( p ){
- p->aSortOrder = (u8*)&p->aColl[N+1];
- p->nField = (u16)N;
- p->enc = ENC(db);
- p->db = db;
- }
- return p;
- }
- /*
- ** Given an expression list, generate a KeyInfo structure that records
- ** the collating sequence for each expression in that expression list.
- **
- ** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
- ** KeyInfo structure is appropriate for initializing a virtual index to
- ** implement that clause. If the ExprList is the result set of a SELECT
- ** then the KeyInfo structure is appropriate for initializing a virtual
- ** index to implement a DISTINCT test.
- **
- ** Space to hold the KeyInfo structure is obtain from malloc. The calling
- ** function is responsible for seeing that this structure is eventually
- ** freed. Add the KeyInfo structure to the P4 field of an opcode using
- ** P4_KEYINFO_HANDOFF is the usual way of dealing with this.
- */
- static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
- int nExpr;
- KeyInfo *pInfo;
- struct ExprList_item *pItem;
- sqlite3 *db = pParse->db;
- int i;
- nExpr = pList->nExpr;
- pInfo = sqlite3KeyInfoAlloc(db, nExpr);
- if( pInfo ){
- for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
- CollSeq *pColl;
- pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
- if( !pColl ) pColl = db->pDfltColl;
- pInfo->aColl[i] = pColl;
- pInfo->aSortOrder[i] = pItem->sortOrder;
- }
- }
- return pInfo;
- }
- #ifndef SQLITE_OMIT_COMPOUND_SELECT
- /*
- ** Name of the connection operator, used for error messages.
- */
- static const char *selectOpName(int id){
- char *z;
- switch( id ){
- case TK_ALL: z = "UNION ALL"; break;
- case TK_INTERSECT: z = "INTERSECT"; break;
- case TK_EXCEPT: z = "EXCEPT"; break;
- default: z = "UNION"; break;
- }
- return z;
- }
- #endif /* SQLITE_OMIT_COMPOUND_SELECT */
- #ifndef SQLITE_OMIT_EXPLAIN
- /*
- ** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
- ** is a no-op. Otherwise, it adds a single row of output to the EQP result,
- ** where the caption is of the form:
- **
- ** "USE TEMP B-TREE FOR xxx"
- **
- ** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
- ** is determined by the zUsage argument.
- */
- static void explainTempTable(Parse *pParse, const char *zUsage){
- if( pParse->explain==2 ){
- Vdbe *v = pParse->pVdbe;
- char *zMsg = sqlite3MPrintf(pParse->db, "USE TEMP B-TREE FOR %s", zUsage);
- sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
- }
- }
- /*
- ** Assign expression b to lvalue a. A second, no-op, version of this macro
- ** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
- ** in sqlite3Select() to assign values to structure member variables that
- ** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
- ** code with #ifndef directives.
- */
- # define explainSetInteger(a, b) a = b
- #else
- /* No-op versions of the explainXXX() functions and macros. */
- # define explainTempTable(y,z)
- # define explainSetInteger(y,z)
- #endif
- #if !defined(SQLITE_OMIT_EXPLAIN) && !defined(SQLITE_OMIT_COMPOUND_SELECT)
- /*
- ** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
- ** is a no-op. Otherwise, it adds a single row of output to the EQP result,
- ** where the caption is of one of the two forms:
- **
- ** "COMPOSITE SUBQUERIES iSub1 and iSub2 (op)"
- ** "COMPOSITE SUBQUERIES iSub1 and iSub2 USING TEMP B-TREE (op)"
- **
- ** where iSub1 and iSub2 are the integers passed as the corresponding
- ** function parameters, and op is the text representation of the parameter
- ** of the same name. The parameter "op" must be one of TK_UNION, TK_EXCEPT,
- ** TK_INTERSECT or TK_ALL. The first form is used if argument bUseTmp is
- ** false, or the second form if it is true.
- */
- static void explainComposite(
- Parse *pParse, /* Parse context */
- int op, /* One of TK_UNION, TK_EXCEPT etc. */
- int iSub1, /* Subquery id 1 */
- int iSub2, /* Subquery id 2 */
- int bUseTmp /* True if a temp table was used */
- ){
- assert( op==TK_UNION || op==TK_EXCEPT || op==TK_INTERSECT || op==TK_ALL );
- if( pParse->explain==2 ){
- Vdbe *v = pParse->pVdbe;
- char *zMsg = sqlite3MPrintf(
- pParse->db, "COMPOUND SUBQUERIES %d AND %d %s(%s)", iSub1, iSub2,
- bUseTmp?"USING TEMP B-TREE ":"", selectOpName(op)
- );
- sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
- }
- }
- #else
- /* No-op versions of the explainXXX() functions and macros. */
- # define explainComposite(v,w,x,y,z)
- #endif
- /*
- ** If the inner loop was generated using a non-null pOrderBy argument,
- ** then the results were placed in a sorter. After the loop is terminated
- ** we need to run the sorter and output the results. The following
- ** routine generates the code needed to do that.
- */
- static void generateSortTail(
- Parse *pParse, /* Parsing context */
- Select *p, /* The SELECT statement */
- Vdbe *v, /* Generate code into this VDBE */
- int nColumn, /* Number of columns of data */
- SelectDest *pDest /* Write the sorted results here */
- ){
- int addrBreak = sqlite3VdbeMakeLabel(v); /* Jump here to exit loop */
- int addrContinue = sqlite3VdbeMakeLabel(v); /* Jump here for next cycle */
- int addr;
- int iTab;
- int pseudoTab = 0;
- ExprList *pOrderBy = p->pOrderBy;
- int eDest = pDest->eDest;
- int iParm = pDest->iSDParm;
- int regRow;
- int regRowid;
- iTab = pOrderBy->iECursor;
- regRow = sqlite3GetTempReg(pParse);
- if( eDest==SRT_Output || eDest==SRT_Coroutine ){
- pseudoTab = pParse->nTab++;
- sqlite3VdbeAddOp3(v, OP_OpenPseudo, pseudoTab, regRow, nColumn);
- regRowid = 0;
- }else{
- regRowid = sqlite3GetTempReg(pParse);
- }
- if( p->selFlags & SF_UseSorter ){
- int regSortOut = ++pParse->nMem;
- int ptab2 = pParse->nTab++;
- sqlite3VdbeAddOp3(v, OP_OpenPseudo, ptab2, regSortOut, pOrderBy->nExpr+2);
- addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
- codeOffset(v, p, addrContinue);
- sqlite3VdbeAddOp2(v, OP_SorterData, iTab, regSortOut);
- sqlite3VdbeAddOp3(v, OP_Column, ptab2, pOrderBy->nExpr+1, regRow);
- sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
- }else{
- addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak);
- codeOffset(v, p, addrContinue);
- sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr+1, regRow);
- }
- switch( eDest ){
- case SRT_Table:
- case SRT_EphemTab: {
- testcase( eDest==SRT_Table );
- testcase( eDest==SRT_EphemTab );
- sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);
- sqlite3VdbeAddOp3(v, OP_Insert, iParm, regRow, regRowid);
- sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
- break;
- }
- #ifndef SQLITE_OMIT_SUBQUERY
- case SRT_Set: {
- assert( nColumn==1 );
- sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, 1, regRowid,
- &pDest->affSdst, 1);
- sqlite3ExprCacheAffinityChange(pParse, regRow, 1);
- sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, regRowid);
- break;
- }
- case SRT_Mem: {
- assert( nColumn==1 );
- sqlite3ExprCodeMove(pParse, regRow, iParm, 1);
- /* The LIMIT clause will terminate the loop for us */
- break;
- }
- #endif
- default: {
- int i;
- assert( eDest==SRT_Output || eDest==SRT_Coroutine );
- testcase( eDest==SRT_Output );
- testcase( eDest==SRT_Coroutine );
- for(i=0; i<nColumn; i++){
- assert( regRow!=pDest->iSdst+i );
- sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iSdst+i);
- if( i==0 ){
- sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
- }
- }
- if( eDest==SRT_Output ){
- sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iSdst, nColumn);
- sqlite3ExprCacheAffinityChange(pParse, pDest->iSdst, nColumn);
- }else{
- sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
- }
- break;
- }
- }
- sqlite3ReleaseTempReg(pParse, regRow);
- sqlite3ReleaseTempReg(pParse, regRowid);
- /* The bottom of the loop
- */
- sqlite3VdbeResolveLabel(v, addrContinue);
- if( p->selFlags & SF_UseSorter ){
- sqlite3VdbeAddOp2(v, OP_SorterNext, iTab, addr);
- }else{
- sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
- }
- sqlite3VdbeResolveLabel(v, addrBreak);
- if( eDest==SRT_Output || eDest==SRT_Coroutine ){
- sqlite3VdbeAddOp2(v, OP_Close, pseudoTab, 0);
- }
- }
- /*
- ** Return a pointer to a string containing the 'declaration type' of the
- ** expression pExpr. The string may be treated as static by the caller.
- **
- ** Also try to estimate the size of the returned value and return that
- ** result in *pEstWidth.
- **
- ** The declaration type is the exact datatype definition extracted from the
- ** original CREATE TABLE statement if the expression is a column. The
- ** declaration type for a ROWID field is INTEGER. Exactly when an expression
- ** is considered a column can be complex in the presence of subqueries. The
- ** result-set expression in all of the following SELECT statements is
- ** considered a column by this function.
- **
- ** SELECT col FROM tbl;
- ** SELECT (SELECT col FROM tbl;
- ** SELECT (SELECT col FROM tbl);
- ** SELECT abc FROM (SELECT col AS abc FROM tbl);
- **
- ** The declaration type for any expression other than a column is NULL.
- **
- ** This routine has either 3 or 6 parameters depending on whether or not
- ** the SQLITE_ENABLE_COLUMN_METADATA compile-time option is used.
- */
- #ifdef SQLITE_ENABLE_COLUMN_METADATA
- # define columnType(A,B,C,D,E,F) columnTypeImpl(A,B,C,D,E,F)
- static const char *columnTypeImpl(
- NameContext *pNC,
- Expr *pExpr,
- const char **pzOrigDb,
- const char **pzOrigTab,
- const char **pzOrigCol,
- u8 *pEstWidth
- ){
- char const *zOrigDb = 0;
- char const *zOrigTab = 0;
- char const *zOrigCol = 0;
- #else /* if !defined(SQLITE_ENABLE_COLUMN_METADATA) */
- # define columnType(A,B,C,D,E,F) columnTypeImpl(A,B,F)
- static const char *columnTypeImpl(
- NameContext *pNC,
- Expr *pExpr,
- u8 *pEstWidth
- ){
- #endif /* !defined(SQLITE_ENABLE_COLUMN_METADATA) */
- char const *zType = 0;
- int j;
- u8 estWidth = 1;
- if( NEVER(pExpr==0) || pNC->pSrcList==0 ) return 0;
- switch( pExpr->op ){
- case TK_AGG_COLUMN:
- case TK_COLUMN: {
- /* The expression is a column. Locate the table the column is being
- ** extracted from in NameContext.pSrcList. This table may be real
- ** database table or a subquery.
- */
- Table *pTab = 0; /* Table structure column is extracted from */
- Select *pS = 0; /* Select the column is extracted from */
- int iCol = pExpr->iColumn; /* Index of column in pTab */
- testcase( pExpr->op==TK_AGG_COLUMN );
- testcase( pExpr->op==TK_COLUMN );
- while( pNC && !pTab ){
- SrcList *pTabList = pNC->pSrcList;
- for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
- if( j<pTabList->nSrc ){
- pTab = pTabList->a[j].pTab;
- pS = pTabList->a[j].pSelect;
- }else{
- pNC = pNC->pNext;
- }
- }
- if( pTab==0 ){
- /* At one time, code such as "SELECT new.x" within a trigger would
- ** cause this condition to run. Since then, we have restructured how
- ** trigger code is generated and so this condition is no longer
- ** possible. However, it can still be true for statements like
- ** the following:
- **
- ** CREATE TABLE t1(col INTEGER);
- ** SELECT (SELECT t1.col) FROM FROM t1;
- **
- ** when columnType() is called on the expression "t1.col" in the
- ** sub-select. In this case, set the column type to NULL, even
- ** though it should really be "INTEGER".
- **
- ** This is not a problem, as the column type of "t1.col" is never
- ** used. When columnType() is called on the expression
- ** "(SELECT t1.col)", the correct type is returned (see the TK_SELECT
- ** branch below. */
- break;
- }
- assert( pTab && pExpr->pTab==pTab );
- if( pS ){
- /* The "table" is actually a sub-select or a view in the FROM clause
- ** of the SELECT statement. Return the declaration type and origin
- ** data for the result-set column of the sub-select.
- */
- if( iCol>=0 && ALWAYS(iCol<pS->pEList->nExpr) ){
- /* If iCol is less than zero, then the expression requests the
- ** rowid of the sub-select or view. This expression is legal (see
- ** test case misc2.2.2) - it always evaluates to NULL.
- */
- NameContext sNC;
- Expr *p = pS->pEList->a[iCol].pExpr;
- sNC.pSrcList = pS->pSrc;
- sNC.pNext = pNC;
- sNC.pParse = pNC->pParse;
- zType = columnType(&sNC, p,&zOrigDb,&zOrigTab,&zOrigCol, &estWidth);
- }
- }else if( ALWAYS(pTab->pSchema) ){
- /* A real table */
- assert( !pS );
- if( iCol<0 ) iCol = pTab->iPKey;
- assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
- #ifdef SQLITE_ENABLE_COLUMN_METADATA
- if( iCol<0 ){
- zType = "INTEGER";
- zOrigCol = "rowid";
- }else{
- zType = pTab->aCol[iCol].zType;
- zOrigCol = pTab->aCol[iCol].zName;
- estWidth = pTab->aCol[iCol].szEst;
- }
- zOrigTab = pTab->zName;
- if( pNC->pParse ){
- int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
- zOrigDb = pNC->pParse->db->aDb[iDb].zName;
- }
- #else
- if( iCol<0 ){
- zType = "INTEGER";
- }else{
- zType = pTab->aCol[iCol].zType;
- estWidth = pTab->aCol[iCol].szEst;
- }
- #endif
- }
- break;
- }
- #ifndef SQLITE_OMIT_SUBQUERY
- case TK_SELECT: {
- /* The expression is a sub-select. Return the declaration type and
- ** origin info for the single column in the result set of the SELECT
- ** statement.
- */
- NameContext sNC;
- Select *pS = pExpr->x.pSelect;
- Expr *p = pS->pEList->a[0].pExpr;
- assert( ExprHasProperty(pExpr, EP_xIsSelect) );
- sNC.pSrcList = pS->pSrc;
- sNC.pNext = pNC;
- sNC.pParse = pNC->pParse;
- zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol, &estWidth);
- break;
- }
- #endif
- }
- #ifdef SQLITE_ENABLE_COLUMN_METADATA
- if( pzOrigDb ){
- assert( pzOrigTab && pzOrigCol );
- *pzOrigDb = zOrigDb;
- *pzOrigTab = zOrigTab;
- *pzOrigCol = zOrigCol;
- }
- #endif
- if( pEstWidth ) *pEstWidth = estWidth;
- return zType;
- }
- /*
- ** Generate code that will tell the VDBE the declaration types of columns
- ** in the result set.
- */
- static void generateColumnTypes(
- Parse *pParse, /* Parser context */
- SrcList *pTabList, /* List of tables */
- ExprList *pEList /* Expressions defining the result set */
- ){
- #ifndef SQLITE_OMIT_DECLTYPE
- Vdbe *v = pParse->pVdbe;
- int i;
- NameContext sNC;
- sNC.pSrcList = pTabList;
- sNC.pParse = pParse;
- for(i=0; i<pEList->nExpr; i++){
- Expr *p = pEList->a[i].pExpr;
- const char *zType;
- #ifdef SQLITE_ENABLE_COLUMN_METADATA
- const char *zOrigDb = 0;
- const char *zOrigTab = 0;
- const char *zOrigCol = 0;
- zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol, 0);
- /* The vdbe must make its own copy of the column-type and other
- ** column specific strings, in case the schema is reset before this
- ** virtual machine is deleted.
- */
- sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, SQLITE_TRANSIENT);
- sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, SQLITE_TRANSIENT);
- sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, SQLITE_TRANSIENT);
- #else
- zType = columnType(&sNC, p, 0, 0, 0, 0);
- #endif
- sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, SQLITE_TRANSIENT);
- }
- #endif /* !defined(SQLITE_OMIT_DECLTYPE) */
- }
- /*
- ** Generate code that will tell the VDBE the names of columns
- ** in the result set. This information is used to provide the
- ** azCol[] values in the callback.
- */
- static void generateColumnNames(
- Parse *pParse, /* Parser context */
- SrcList *pTabList, /* List of tables */
- ExprList *pEList /* Expressions defining the result set */
- ){
- Vdbe *v = pParse->pVdbe;
- int i, j;
- sqlite3 *db = pParse->db;
- int fullNames, shortNames;
- #ifndef SQLITE_OMIT_EXPLAIN
- /* If this is an EXPLAIN, skip this step */
- if( pParse->explain ){
- return;
- }
- #endif
- if( pParse->colNamesSet || NEVER(v==0) || db->mallocFailed ) return;
- pParse->colNamesSet = 1;
- fullNames = (db->flags & SQLITE_FullColNames)!=0;
- shortNames = (db->flags & SQLITE_ShortColNames)!=0;
- sqlite3VdbeSetNumCols(v, pEList->nExpr);
- for(i=0; i<pEList->nExpr; i++){
- Expr *p;
- p = pEList->a[i].pExpr;
- if( NEVER(p==0) ) continue;
- if( pEList->a[i].zName ){
- char *zName = pEList->a[i].zName;
- sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_TRANSIENT);
- }else if( (p->op==TK_COLUMN || p->op==TK_AGG_COLUMN) && pTabList ){
- Table *pTab;
- char *zCol;
- int iCol = p->iColumn;
- for(j=0; ALWAYS(j<pTabList->nSrc); j++){
- if( pTabList->a[j].iCursor==p->iTable ) break;
- }
- assert( j<pTabList->nSrc );
- pTab = pTabList->a[j].pTab;
- if( iCol<0 ) iCol = pTab->iPKey;
- assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
- if( iCol<0 ){
- zCol = "rowid";
- }else{
- zCol = pTab->aCol[iCol].zName;
- }
- if( !shortNames && !fullNames ){
- sqlite3VdbeSetColName(v, i, COLNAME_NAME,
- sqlite3DbStrDup(db, pEList->a[i].zSpan), SQLITE_DYNAMIC);
- }else if( fullNames ){
- char *zName = 0;
- zName = sqlite3MPrintf(db, "%s.%s", pTab->zName, zCol);
- sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, SQLITE_DYNAMIC);
- }else{
- sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, SQLITE_TRANSIENT);
- }
- }else{
- sqlite3VdbeSetColName(v, i, COLNAME_NAME,
- sqlite3DbStrDup(db, pEList->a[i].zSpan), SQLITE_DYNAMIC);
- }
- }
- generateColumnTypes(pParse, pTabList, pEList);
- }
- /*
- ** Given a an expression list (which is really the list of expressions
- ** that form the result set of a SELECT statement) compute appropriate
- ** column names for a table that would hold the expression list.
- **
- ** All column names will be unique.
- **
- ** Only the column names are computed. Column.zType, Column.zColl,
- ** and other fields of Column are zeroed.
- **
- ** Return SQLITE_OK on success. If a memory allocation error occurs,
- ** store NULL in *paCol and 0 in *pnCol and return SQLITE_NOMEM.
- */
- static int selectColumnsFromExprList(
- Parse *pParse, /* Parsing context */
- ExprList *pEList, /* Expr list from which to derive column names */
- i16 *pnCol, /* Write the number of columns here */
- Column **paCol /* Write the new column list here */
- ){
- sqlite3 *db = pParse->db; /* Database connection */
- int i, j; /* Loop counters */
- int cnt; /* Index added to make the name unique */
- Column *aCol, *pCol; /* For looping over result columns */
- int nCol; /* Number of columns in the result set */
- Expr *p; /* Expression for a single result column */
- char *zName; /* Column name */
- int nName; /* Size of name in zName[] */
- if( pEList ){
- nCol = pEList->nExpr;
- aCol = sqlite3DbMallocZero(db, sizeof(aCol[0])*nCol);
- testcase( aCol==0 );
- }else{
- nCol = 0;
- aCol = 0;
- }
- *pnCol = nCol;
- *paCol = aCol;
- for(i=0, pCol=aCol; i<nCol; i++, pCol++){
- /* Get an appropriate name for the column
- */
- p = sqlite3ExprSkipCollate(pEList->a[i].pExpr);
- if( (zName = pEList->a[i].zName)!=0 ){
- /* If the column contains an "AS <name>" phrase, use <name> as the name */
- zName = sqlite3DbStrDup(db, zName);
- }else{
- Expr *pColExpr = p; /* The expression that is the result column name */
- Table *pTab; /* Table associated with this expression */
- while( pColExpr->op==TK_DOT ){
- pColExpr = pColExpr->pRight;
- assert( pColExpr!=0 );
- }
- if( pColExpr->op==TK_COLUMN && ALWAYS(pColExpr->pTab!=0) ){
- /* For columns use the column name name */
- int iCol = pColExpr->iColumn;
- pTab = pColExpr->pTab;
- if( iCol<0 ) iCol = pTab->iPKey;
- zName = sqlite3MPrintf(db, "%s",
- iCol>=0 ? pTab->aCol[iCol].zName : "rowid");
- }else if( pColExpr->op==TK_ID ){
- assert( !ExprHasProperty(pColExpr, EP_IntValue) );
- zName = sqlite3MPrintf(db, "%s", pColExpr->u.zToken);
- }else{
- /* Use the original text of the column expression as its name */
- zName = sqlite3MPrintf(db, "%s", pEList->a[i].zSpan);
- }
- }
- if( db->mallocFailed ){
- sqlite3DbFree(db, zName);
- break;
- }
- /* Make sure the column name is unique. If the name is not unique,
- ** append a integer to the name so that it becomes unique.
- */
- nName = sqlite3Strlen30(zName);
- for(j=cnt=0; j<i; j++){
- if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
- char *zNewName;
- int k;
- for(k=nName-1; k>1 && sqlite3Isdigit(zName[k]); k--){}
- if( zName[k]==':' ) nName = k;
- zName[nName] = 0;
- zNewName = sqlite3MPrintf(db, "%s:%d", zName, ++cnt);
- sqlite3DbFree(db, zName);
- zName = zNewName;
- j = -1;
- if( zName==0 ) break;
- }
- }
- pCol->zName = zName;
- }
- if( db->mallocFailed ){
- for(j=0; j<i; j++){
- sqlite3DbFree(db, aCol[j].zName);
- }
- sqlite3DbFree(db, aCol);
- *paCol = 0;
- *pnCol = 0;
- return SQLITE_NOMEM;
- }
- return SQLITE_OK;
- }
- /*
- ** Add type and collation information to a column list based on
- ** a SELECT statement.
- **
- ** The column list presumably came from selectColumnNamesFromExprList().
- ** The column list has only names, not types or collations. This
- ** routine goes through and adds the types and collations.
- **
- ** This routine requires that all identifiers in the SELECT
- ** statement be resolved.
- */
- static void selectAddColumnTypeAndCollation(
- Parse *pParse, /* Parsing contexts */
- Table *pTab, /* Add column type information to this table */
- Select *pSelect /* SELECT used to determine types and collations */
- ){
- sqlite3 *db = pParse->db;
- NameContext sNC;
- Column *pCol;
- CollSeq *pColl;
- int i;
- Expr *p;
- struct ExprList_item *a;
- u64 szAll = 0;
- assert( pSelect!=0 );
- assert( (pSelect->selFlags & SF_Resolved)!=0 );
- assert( pTab->nCol==pSelect->pEList->nExpr || db->mallocFailed );
- if( db->mallocFailed ) return;
- memset(&sNC, 0, sizeof(sNC));
- sNC.pSrcList = pSelect->pSrc;
- a = pSelect->pEList->a;
- for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
- p = a[i].pExpr;
- pCol->zType = sqlite3DbStrDup(db, columnType(&sNC, p,0,0,0, &pCol->szEst));
- szAll += pCol->szEst;
- pCol->affinity = sqlite3ExprAffinity(p);
- if( pCol->affinity==0 ) pCol->affinity = SQLITE_AFF_NONE;
- pColl = sqlite3ExprCollSeq(pParse, p);
- if( pColl ){
- pCol->zColl = sqlite3DbStrDup(db, pColl->zName);
- }
- }
- pTab->szTabRow = sqlite3LogEst(szAll*4);
- }
- /*
- ** Given a SELECT statement, generate a Table structure that describes
- ** the result set of that SELECT.
- */
- Table *sqlite3ResultSetOfSelect(Parse *pParse, Select *pSelect){
- Table *pTab;
- sqlite3 *db = pParse->db;
- int savedFlags;
- savedFlags = db->flags;
- db->flags &= ~SQLITE_FullColNames;
- db->flags |= SQLITE_ShortColNames;
- sqlite3SelectPrep(pParse, pSelect, 0);
- if( pParse->nErr ) return 0;
- while( pSelect->pPrior ) pSelect = pSelect->pPrior;
- db->flags = savedFlags;
- pTab = sqlite3DbMallocZero(db, sizeof(Table) );
- if( pTab==0 ){
- return 0;
- }
- /* The sqlite3ResultSetOfSelect() is only used n contexts where lookaside
- ** is disabled */
- assert( db->lookaside.bEnabled==0 );
- pTab->nRef = 1;
- pTab->zName = 0;
- pTab->nRowEst = 1048576;
- selectColumnsFromExprList(pParse, pSelect->pEList, &pTab->nCol, &pTab->aCol);
- selectAddColumnTypeAndCollation(pParse, pTab, pSelect);
- pTab->iPKey = -1;
- if( db->mallocFailed ){
- sqlite3DeleteTable(db, pTab);
- return 0;
- }
- return pTab;
- }
- /*
- ** Get a VDBE for the given parser context. Create a new one if necessary.
- ** If an error occurs, return NULL and leave a message in pParse.
- */
- Vdbe *sqlite3GetVdbe(Parse *pParse){
- Vdbe *v = pParse->pVdbe;
- if( v==0 ){
- v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
- #ifndef SQLITE_OMIT_TRACE
- if( v ){
- sqlite3VdbeAddOp0(v, OP_Trace);
- }
- #endif
- }
- return v;
- }
- /*
- ** Compute the iLimit and iOffset fields of the SELECT based on the
- ** pLimit and pOffset expressions. pLimit and pOffset hold the expressions
- ** that appear in the original SQL statement after the LIMIT and OFFSET
- ** keywords. Or NULL if those keywords are omitted. iLimit and iOffset
- ** are the integer memory register numbers for counters used to compute
- ** the limit and offset. If there is no limit and/or offset, then
- ** iLimit and iOffset are negative.
- **
- ** This routine changes the values of iLimit and iOffset only if
- ** a limit or offset is defined by pLimit and pOffset. iLimit and
- ** iOffset should have been preset to appropriate default values
- ** (usually but not always -1) prior to calling this routine.
- ** Only if pLimit!=0 or pOffset!=0 do the limit registers get
- ** redefined. The UNION ALL operator uses this property to force
- ** the reuse of the same limit and offset registers across multiple
- ** SELECT statements.
- */
- static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
- Vdbe *v = 0;
- int iLimit = 0;
- int iOffset;
- int addr1, n;
- if( p->iLimit ) return;
- /*
- ** "LIMIT -1" always shows all rows. There is some
- ** controversy about what the correct behavior should be.
- ** The current implementation interprets "LIMIT 0" to mean
- ** no rows.
- */
- sqlite3ExprCacheClear(pParse);
- assert( p->pOffset==0 || p->pLimit!=0 );
- if( p->pLimit ){
- p->iLimit = iLimit = ++pParse->nMem;
- v = sqlite3GetVdbe(pParse);
- if( NEVER(v==0) ) return; /* VDBE should have already been allocated */
- if( sqlite3ExprIsInteger(p->pLimit, &n) ){
- sqlite3VdbeAddOp2(v, OP_Integer, n, iLimit);
- VdbeComment((v, "LIMIT counter"));
- if( n==0 ){
- sqlite3VdbeAddOp2(v, OP_Goto, 0, iBreak);
- }else if( n>=0 && p->nSelectRow>(u64)n ){
- p->nSelectRow = n;
- }
- }else{
- sqlite3ExprCode(pParse, p->pLimit, iLimit);
- sqlite3VdbeAddOp1(v, OP_MustBeInt, iLimit);
- VdbeComment((v, "LIMIT counter"));
- sqlite3VdbeAddOp2(v, OP_IfZero, iLimit, iBreak);
- }
- if( p->pOffset ){
- p->iOffset = iOffset = ++pParse->nMem;
- pParse->nMem++; /* Allocate an extra register for limit+offset */
- sqlite3ExprCode(pParse, p->pOffset, iOffset);
- sqlite3VdbeAddOp1(v, OP_MustBeInt, iOffset);
- VdbeComment((v, "OFFSET counter"));
- addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iOffset);
- sqlite3VdbeAddOp2(v, OP_Integer, 0, iOffset);
- sqlite3VdbeJumpHere(v, addr1);
- sqlite3VdbeAddOp3(v, OP_Add, iLimit, iOffset, iOffset+1);
- VdbeComment((v, "LIMIT+OFFSET"));
- addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
- sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
- sqlite3VdbeJumpHere(v, addr1);
- }
- }
- }
- #ifndef SQLITE_OMIT_COMPOUND_SELECT
- /*
- ** Return the appropriate collating sequence for the iCol-th column of
- ** the result set for the compound-select statement "p". Return NULL if
- ** the column has no default collating sequence.
- **
- ** The collating sequence for the compound select is taken from the
- ** left-most term of the select that has a collating sequence.
- */
- static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
- CollSeq *pRet;
- if( p->pPrior ){
- pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
- }else{
- pRet = 0;
- }
- assert( iCol>=0 );
- if( pRet==0 && iCol<p->pEList->nExpr ){
- pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
- }
- return pRet;
- }
- #endif /* SQLITE_OMIT_COMPOUND_SELECT */
- /* Forward reference */
- static int multiSelectOrderBy(
- Parse *pParse, /* Parsing context */
- Select *p, /* The right-most of SELECTs to be coded */
- SelectDest *pDest /* What to do with query results */
- );
- #ifndef SQLITE_OMIT_COMPOUND_SELECT
- /*
- ** This routine is called to process a compound query form from
- ** two or more separate queries using UNION, UNION ALL, EXCEPT, or
- ** INTERSECT
- **
- ** "p" points to the right-most of the two queries. the query on the
- ** left is p->pPrior. The left query could also be a compound query
- ** in which case this routine will be called recursively.
- **
- ** The results of the total query are to be written into a destination
- ** of type eDest with parameter iParm.
- **
- ** Example 1: Consider a three-way compound SQL statement.
- **
- ** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
- **
- ** This statement is parsed up as follows:
- **
- ** SELECT c FROM t3
- ** |
- ** `-----> SELECT b FROM t2
- ** |
- ** `------> SELECT a FROM t1
- **
- ** The arrows in the diagram above represent the Select.pPrior pointer.
- ** So if this routine is called with p equal to the t3 query, then
- ** pPrior will be the t2 query. p->op will be TK_UNION in this case.
- **
- ** Notice that because of the way SQLite parses compound SELECTs, the
- ** individual selects always group from left to right.
- */
- static int multiSelect(
- Parse *pParse, /* Parsing context */
- Select *p, /* The right-most of SELECTs to be coded */
- SelectDest *pDest /* What to do with query results */
- ){
- int rc = SQLITE_OK; /* Success code from a subroutine */
- Select *pPrior; /* Another SELECT immediately to our left */
- Vdbe *v; /* Generate code to this VDBE */
- SelectDest dest; /* Alternative data destination */
- Select *pDelete = 0; /* Chain of simple selects to delete */
- sqlite3 *db; /* Database connection */
- #ifndef SQLITE_OMIT_EXPLAIN
- int iSub1; /* EQP id of left-hand query */
- int iSub2; /* EQP id of right-hand query */
- #endif
- /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
- ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
- */
- assert( p && p->pPrior ); /* Calling function guarantees this much */
- db = pParse->db;
- pPrior = p->pPrior;
- assert( pPrior->pRightmost!=pPrior );
- assert( pPrior->pRightmost==p->pRightmost );
- dest = *pDest;
- if( pPrior->pOrderBy ){
- sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
- selectOpName(p->op));
- rc = 1;
- goto multi_select_end;
- }
- if( pPrior->pLimit ){
- sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
- selectOpName(p->op));
- rc = 1;
- goto multi_select_end;
- }
- v = sqlite3GetVdbe(pParse);
- assert( v!=0 ); /* The VDBE already created by calling function */
- /* Create the destination temporary table if necessary
- */
- if( dest.eDest==SRT_EphemTab ){
- assert( p->pEList );
- sqlite3VdbeAddOp2(v, OP_OpenEphemeral, dest.iSDParm, p->pEList->nExpr);
- sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
- dest.eDest = SRT_Table;
- }
- /* Make sure all SELECTs in the statement have the same number of elements
- ** in their result sets.
- */
- assert( p->pEList && pPrior->pEList );
- if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
- if( p->selFlags & SF_Values ){
- sqlite3ErrorMsg(pParse, "all VALUES must have the same number of terms");
- }else{
- sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
- " do not have the same number of result columns", selectOpName(p->op));
- }
- rc = 1;
- goto multi_select_end;
- }
- /* Compound SELECTs that have an ORDER BY clause are handled separately.
- */
- if( p->pOrderBy ){
- return multiSelectOrderBy(pParse, p, pDest);
- }
- /* Generate code for the left and right SELECT statements.
- */
- switch( p->op ){
- case TK_ALL: {
- int addr = 0;
- int nLimit;
- assert( !pPrior->pLimit );
- pPrior->iLimit = p->iLimit;
- pPrior->iOffset = p->iOffset;
- pPrior->pLimit = p->pLimit;
- pPrior->pOffset = p->pOffset;
- explainSetInteger(iSub1, pParse->iNextSelectId);
- rc = sqlite3Select(pParse, pPrior, &dest);
- p->pLimit = 0;
- p->pOffset = 0;
- if( rc ){
- goto multi_select_end;
- }
- p->pPrior = 0;
- p->iLimit = pPrior->iLimit;
- p->iOffset = pPrior->iOffset;
- if( p->iLimit ){
- addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
- VdbeComment((v, "Jump ahead if LIMIT reached"));
- }
- explainSetInteger(iSub2, pParse->iNextSelectId);
- rc = sqlite3Select(pParse, p, &dest);
- testcase( rc!=SQLITE_OK );
- pDelete = p->pPrior;
- p->pPrior = pPrior;
- p->nSelectRow += pPrior->nSelectRow;
- if( pPrior->pLimit
- && sqlite3ExprIsInteger(pPrior->pLimit, &nLimit)
- && nLimit>0 && p->nSelectRow > (u64)nLimit
- ){
- p->nSelectRow = nLimit;
- }
- if( addr ){
- sqlite3VdbeJumpHere(v, addr);
- }
- break;
- }
- case TK_EXCEPT:
- case TK_UNION: {
- int unionTab; /* Cursor number of the temporary table holding result */
- u8 op = 0; /* One of the SRT_ operations to apply to self */
- int priorOp; /* The SRT_ operation to apply to prior selects */
- Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
- int addr;
- SelectDest uniondest;
- testcase( p->op==TK_EXCEPT );
- testcase( p->op==TK_UNION );
- priorOp = SRT_Union;
- if( dest.eDest==priorOp && ALWAYS(!p->pLimit &&!p->pOffset) ){
- /* We can reuse a temporary table generated by a SELECT to our
- ** right.
- */
- assert( p->pRightmost!=p ); /* Can only happen for leftward elements
- ** of a 3-way or more compound */
- assert( p->pLimit==0 ); /* Not allowed on leftward elements */
- assert( p->pOffset==0 ); /* Not allowed on leftward elements */
- unionTab = dest.iSDParm;
- }else{
- /* We will need to create our own temporary table to hold the
- ** intermediate results.
- */
- unionTab = pParse->nTab++;
- assert( p->pOrderBy==0 );
- addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, unionTab, 0);
- assert( p->addrOpenEphm[0] == -1 );
- p->addrOpenEphm[0] = addr;
- p->pRightmost->selFlags |= SF_UsesEphemeral;
- assert( p->pEList );
- }
- /* Code the SELECT statements to our left
- */
- assert( !pPrior->pOrderBy );
- sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
- explainSetInteger(iSub1, pParse->iNextSelectId);
- rc = sqlite3Select(pParse, pPrior, &uniondest);
- if( rc ){
- goto multi_select_end;
- }
- /* Code the current SELECT statement
- */
- if( p->op==TK_EXCEPT ){
- op = SRT_Except;
- }else{
- assert( p->op==TK_UNION );
- op = SRT_Union;
- }
- p->pPrior = 0;
- pLimit = p->pLimit;
- p->pLimit = 0;
- pOffset = p->pOffset;
- p->pOffset = 0;
- uniondest.eDest = op;
- explainSetInteger(iSub2, pParse->iNextSelectId);
- rc = sqlite3Select(pParse, p, &uniondest);
- testcase( rc!=SQLITE_OK );
- /* Query flattening in sqlite3Select() might refill p->pOrderBy.
- ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
- sqlite3ExprListDelete(db, p->pOrderBy);
- pDelete = p->pPrior;
- p->pPrior = pPrior;
- p->pOrderBy = 0;
- if( p->op==TK_UNION ) p->nSelectRow += pPrior->nSelectRow;
- sqlite3ExprDelete(db, p->pLimit);
- p->pLimit = pLimit;
- p->pOffset = pOffset;
- p->iLimit = 0;
- p->iOffset = 0;
- /* Convert the data in the temporary table into whatever form
- ** it is that we currently need.
- */
- assert( unionTab==dest.iSDParm || dest.eDest!=priorOp );
- if( dest.eDest!=priorOp ){
- int iCont, iBreak, iStart;
- assert( p->pEList );
- if( dest.eDest==SRT_Output ){
- Select *pFirst = p;
- while( pFirst->pPrior ) pFirst = pFirst->pPrior;
- generateColumnNames(pParse, 0, pFirst->pEList);
- }
- iBreak = sqlite3VdbeMakeLabel(v);
- iCont = sqlite3VdbeMakeLabel(v);
- computeLimitRegisters(pParse, p, iBreak);
- sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak);
- iStart = sqlite3VdbeCurrentAddr(v);
- selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
- 0, 0, &dest, iCont, iBreak);
- sqlite3VdbeResolveLabel(v, iCont);
- sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart);
- sqlite3VdbeResolveLabel(v, iBreak);
- sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
- }
- break;
- }
- default: assert( p->op==TK_INTERSECT ); {
- int tab1, tab2;
- int iCont, iBreak, iStart;
- Expr *pLimit, *pOffset;
- int addr;
- SelectDest intersectdest;
- int r1;
- /* INTERSECT is different from the others since it requires
- ** two temporary tables. Hence it has its own case. Begin
- ** by allocating the tables we will need.
- */
- tab1 = pParse->nTab++;
- tab2 = pParse->nTab++;
- assert( p->pOrderBy==0 );
- addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
- assert( p->addrOpenEphm[0] == -1 );
- p->addrOpenEphm[0] = addr;
- p->pRightmost->selFlags |= SF_UsesEphemeral;
- assert( p->pEList );
- /* Code the SELECTs to our left into temporary table "tab1".
- */
- sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
- explainSetInteger(iSub1, pParse->iNextSelectId);
- rc = sqlite3Select(pParse, pPrior, &intersectdest);
- if( rc ){
- goto multi_select_end;
- }
- /* Code the current SELECT into temporary table "tab2"
- */
- addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
- assert( p->addrOpenEphm[1] == -1 );
- p->addrOpenEphm[1] = addr;
- p->pPrior = 0;
- pLimit = p->pLimit;
- p->pLimit = 0;
- pOffset = p->pOffset;
- p->pOffset = 0;
- intersectdest.iSDParm = tab2;
- explainSetInteger(iSub2, pParse->iNextSelectId);
- rc = sqlite3Select(pParse, p, &intersectdest);
- testcase( rc!=SQLITE_OK );
- pDelete = p->pPrior;
- p->pPrior = pPrior;
- if( p->nSelectRow>pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
- sqlite3ExprDelete(db, p->pLimit);
- p->pLimit = pLimit;
- p->pOffset = pOffset;
- /* Generate code to take the intersection of the two temporary
- ** tables.
- */
- assert( p->pEList );
- if( dest.eDest==SRT_Output ){
- Select *pFirst = p;
- while( pFirst->pPrior ) pFirst = pFirst->pPrior;
- generateColumnNames(pParse, 0, pFirst->pEList);
- }
- iBreak = sqlite3VdbeMakeLabel(v);
- iCont = sqlite3VdbeMakeLabel(v);
- computeLimitRegisters(pParse, p, iBreak);
- sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
- r1 = sqlite3GetTempReg(pParse);
- iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
- sqlite3VdbeAddOp4Int(v, OP_NotFound, tab2, iCont, r1, 0);
- sqlite3ReleaseTempReg(pParse, r1);
- selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
- 0, 0, &dest, iCont, iBreak);
- sqlite3VdbeResolveLabel(v, iCont);
- sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
- sqlite3VdbeResolveLabel(v, iBreak);
- sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
- sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
- break;
- }
- }
- explainComposite(pParse, p->op, iSub1, iSub2, p->op!=TK_ALL);
- /* Compute collating sequences used by
- ** temporary tables needed to implement the compound select.
- ** Attach the KeyInfo structure to all temporary tables.
- **
- ** This section is run by the right-most SELECT statement only.
- ** SELECT statements to the left always skip this part. The right-most
- ** SELECT might also skip this part if it has no ORDER BY clause and
- ** no temp tables are required.
- */
- if( p->selFlags & SF_UsesEphemeral ){
- int i; /* Loop counter */
- KeyInfo *pKeyInfo; /* Collating sequence for the result set */
- Select *pLoop; /* For looping through SELECT statements */
- CollSeq **apColl; /* For looping through pKeyInfo->aColl[] */
- int nCol; /* Number of columns in result set */
- assert( p->pRightmost==p );
- nCol = p->pEList->nExpr;
- pKeyInfo = sqlite3KeyInfoAlloc(db, nCol);
- if( !pKeyInfo ){
- rc = SQLITE_NOMEM;
- goto multi_select_end;
- }
- for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
- *apColl = multiSelectCollSeq(pParse, p, i);
- if( 0==*apColl ){
- *apColl = db->pDfltColl;
- }
- }
- for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
- for(i=0; i<2; i++){
- int addr = pLoop->addrOpenEphm[i];
- if( addr<0 ){
- /* If [0] is unused then [1] is also unused. So we can
- ** always safely abort as soon as the first unused slot is found */
- assert( pLoop->addrOpenEphm[1]<0 );
- break;
- }
- sqlite3VdbeChangeP2(v, addr, nCol);
- sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
- pLoop->addrOpenEphm[i] = -1;
- }
- }
- sqlite3DbFree(db, pKeyInfo);
- }
- multi_select_end:
- pDest->iSdst = dest.iSdst;
- pDest->nSdst = dest.nSdst;
- sqlite3SelectDelete(db, pDelete);
- return rc;
- }
- #endif /* SQLITE_OMIT_COMPOUND_SELECT */
- /*
- ** Code an output subroutine for a coroutine implementation of a
- ** SELECT statment.
- **
- ** The data to be output is contained in pIn->iSdst. There are
- ** pIn->nSdst columns to be output. pDest is where the output should
- ** be sent.
- **
- ** regReturn is the number of the register holding the subroutine
- ** return address.
- **
- ** If regPrev>0 then it is the first register in a vector that
- ** records the previous output. mem[regPrev] is a flag that is false
- ** if there has been no previous output. If regPrev>0 then code is
- ** generated to suppress duplicates. pKeyInfo is used for comparing
- ** keys.
- **
- ** If the LIMIT found in p->iLimit is reached, jump immediately to
- ** iBreak.
- */
- static int generateOutputSubroutine(
- Parse *pParse, /* Parsing context */
- Select *p, /* The SELECT statement */
- SelectDest *pIn, /* Coroutine supplying data */
- SelectDest *pDest, /* Where to send the data */
- int regReturn, /* The return address register */
- int regPrev, /* Previous result register. No uniqueness if 0 */
- KeyInfo *pKeyInfo, /* For comparing with previous entry */
- int p4type, /* The p4 type for pKeyInfo */
- int iBreak /* Jump here if we hit the LIMIT */
- ){
- Vdbe *v = pParse->pVdbe;
- int iContinue;
- int addr;
- addr = sqlite3VdbeCurrentAddr(v);
- iContinue = sqlite3VdbeMakeLabel(v);
- /* Suppress duplicates for UNION, EXCEPT, and INTERSECT
- */
- if( regPrev ){
- int j1, j2;
- j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
- j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iSdst, regPrev+1, pIn->nSdst,
- (char*)pKeyInfo, p4type);
- sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
- sqlite3VdbeJumpHere(v, j1);
- sqlite3VdbeAddOp3(v, OP_Copy, pIn->iSdst, regPrev+1, pIn->nSdst-1);
- sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
- }
- if( pParse->db->mallocFailed ) return 0;
- /* Suppress the first OFFSET entries if there is an OFFSET clause
- */
- codeOffset(v, p, iContinue);
- switch( pDest->eDest ){
- /* Store the result as data using a unique key.
- */
- case SRT_Table:
- case SRT_EphemTab: {
- int r1 = sqlite3GetTempReg(pParse);
- int r2 = sqlite3GetTempReg(pParse);
- testcase( pDest->eDest==SRT_Table );
- testcase( pDest->eDest==SRT_EphemTab );
- sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst, r1);
- sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iSDParm, r2);
- sqlite3VdbeAddOp3(v, OP_Insert, pDest->iSDParm, r1, r2);
- sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
- sqlite3ReleaseTempReg(pParse, r2);
- sqlite3ReleaseTempReg(pParse, r1);
- break;
- }
- #ifndef SQLITE_OMIT_SUBQUERY
- /* If we are creating a set for an "expr IN (SELECT ...)" construct,
- ** then there should be a single item on the stack. Write this
- ** item into the set table with bogus data.
- */
- case SRT_Set: {
- int r1;
- assert( pIn->nSdst==1 );
- pDest->affSdst =
- sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affSdst);
- r1 = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, 1, r1, &pDest->affSdst,1);
- sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, 1);
- sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iSDParm, r1);
- sqlite3ReleaseTempReg(pParse, r1);
- break;
- }
- #if 0 /* Never occurs on an ORDER BY query */
- /* If any row exist in the result set, record that fact and abort.
- */
- case SRT_Exists: {
- sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iSDParm);
- /* The LIMIT clause will terminate the loop for us */
- break;
- }
- #endif
- /* If this is a scalar select that is part of an expression, then
- ** store the results in the appropriate memory cell and break out
- ** of the scan loop.
- */
- case SRT_Mem: {
- assert( pIn->nSdst==1 );
- sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSDParm, 1);
- /* The LIMIT clause will jump out of the loop for us */
- break;
- }
- #endif /* #ifndef SQLITE_OMIT_SUBQUERY */
- /* The results are stored in a sequence of registers
- ** starting at pDest->iSdst. Then the co-routine yields.
- */
- case SRT_Coroutine: {
- if( pDest->iSdst==0 ){
- pDest->iSdst = sqlite3GetTempRange(pParse, pIn->nSdst);
- pDest->nSdst = pIn->nSdst;
- }
- sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSdst, pDest->nSdst);
- sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
- break;
- }
- /* If none of the above, then the result destination must be
- ** SRT_Output. This routine is never called with any other
- ** destination other than the ones handled above or SRT_Output.
- **
- ** For SRT_Output, results are stored in a sequence of registers.
- ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
- ** return the next row of result.
- */
- default: {
- assert( pDest->eDest==SRT_Output );
- sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst);
- sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, pIn->nSdst);
- break;
- }
- }
- /* Jump to the end of the loop if the LIMIT is reached.
- */
- if( p->iLimit ){
- sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
- }
- /* Generate the subroutine return
- */
- sqlite3VdbeResolveLabel(v, iContinue);
- sqlite3VdbeAddOp1(v, OP_Return, regReturn);
- return addr;
- }
- /*
- ** Alternative compound select code generator for cases when there
- ** is an ORDER BY clause.
- **
- ** We assume a query of the following form:
- **
- ** <selectA> <operator> <selectB> ORDER BY <orderbylist>
- **
- ** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT. The idea
- ** is to code both <selectA> and <selectB> with the ORDER BY clause as
- ** co-routines. Then run the co-routines in parallel and merge the results
- ** into the output. In addition to the two coroutines (called selectA and
- ** selectB) there are 7 subroutines:
- **
- ** outA: Move the output of the selectA coroutine into the output
- ** of the compound query.
- **
- ** outB: Move the output of the selectB coroutine into the output
- ** of the compound query. (Only generated for UNION and
- ** UNION ALL. EXCEPT and INSERTSECT never output a row that
- ** appears only in B.)
- **
- ** AltB: Called when there is data from both coroutines and A<B.
- **
- ** AeqB: Called when there is data from both coroutines and A==B.
- **
- ** AgtB: Called when there is data from both coroutines and A>B.
- **
- ** EofA: Called when data is exhausted from selectA.
- **
- ** EofB: Called when data is exhausted from selectB.
- **
- ** The implementation of the latter five subroutines depend on which
- ** <operator> is used:
- **
- **
- ** UNION ALL UNION EXCEPT INTERSECT
- ** ------------- ----------------- -------------- -----------------
- ** AltB: outA, nextA outA, nextA outA, nextA nextA
- **
- ** AeqB: outA, nextA nextA nextA outA, nextA
- **
- ** AgtB: outB, nextB outB, nextB nextB nextB
- **
- ** EofA: outB, nextB outB, nextB halt halt
- **
- ** EofB: outA, nextA outA, nextA outA, nextA halt
- **
- ** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
- ** causes an immediate jump to EofA and an EOF on B following nextB causes
- ** an immediate jump to EofB. Within EofA and EofB, and EOF on entry or
- ** following nextX causes a jump to the end of the select processing.
- **
- ** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
- ** within the output subroutine. The regPrev register set holds the previously
- ** output value. A comparison is made against this value and the output
- ** is skipped if the next results would be the same as the previous.
- **
- ** The implementation plan is to implement the two coroutines and seven
- ** subroutines first, then put the control logic at the bottom. Like this:
- **
- ** goto Init
- ** coA: coroutine for left query (A)
- ** coB: coroutine for right query (B)
- ** outA: output one row of A
- ** outB: output one row of B (UNION and UNION ALL only)
- ** EofA: ...
- ** EofB: ...
- ** AltB: ...
- ** AeqB: ...
- ** AgtB: ...
- ** Init: initialize coroutine registers
- ** yield coA
- ** if eof(A) goto EofA
- ** yield coB
- ** if eof(B) goto EofB
- ** Cmpr: Compare A, B
- ** Jump AltB, AeqB, AgtB
- ** End: ...
- **
- ** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
- ** actually called using Gosub and they do not Return. EofA and EofB loop
- ** until all data is exhausted then jump to the "end" labe. AltB, AeqB,
- ** and AgtB jump to either L2 or to one of EofA or EofB.
- */
- #ifndef SQLITE_OMIT_COMPOUND_SELECT
- static int multiSelectOrderBy(
- Parse *pParse, /* Parsing context */
- Select *p, /* The right-most of SELECTs to be coded */
- SelectDest *pDest /* What to do with query results */
- ){
- int i, j; /* Loop counters */
- Select *pPrior; /* Another SELECT immediately to our left */
- Vdbe *v; /* Generate code to this VDBE */
- SelectDest destA; /* Destination for coroutine A */
- SelectDest destB; /* Destination for coroutine B */
- int regAddrA; /* Address register for select-A coroutine */
- int regEofA; /* Flag to indicate when select-A is complete */
- int regAddrB; /* Address register for select-B coroutine */
- int regEofB; /* Flag to indicate when select-B is complete */
- int addrSelectA; /* Address of the select-A coroutine */
- int addrSelectB; /* Address of the select-B coroutine */
- int regOutA; /* Address register for the output-A subroutine */
- int regOutB; /* Address register for the output-B subroutine */
- int addrOutA; /* Address of the output-A subroutine */
- int addrOutB = 0; /* Address of the output-B subroutine */
- int addrEofA; /* Address of the select-A-exhausted subroutine */
- int addrEofB; /* Address of the select-B-exhausted subroutine */
- int addrAltB; /* Address of the A<B subroutine */
- int addrAeqB; /* Address of the A==B subroutine */
- int addrAgtB; /* Address of the A>B subroutine */
- int regLimitA; /* Limit register for select-A */
- int regLimitB; /* Limit register for select-A */
- int regPrev; /* A range of registers to hold previous output */
- int savedLimit; /* Saved value of p->iLimit */
- int savedOffset; /* Saved value of p->iOffset */
- int labelCmpr; /* Label for the start of the merge algorithm */
- int labelEnd; /* Label for the end of the overall SELECT stmt */
- int j1; /* Jump instructions that get retargetted */
- int op; /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
- KeyInfo *pKeyDup = 0; /* Comparison information for duplicate removal */
- KeyInfo *pKeyMerge; /* Comparison information for merging rows */
- sqlite3 *db; /* Database connection */
- ExprList *pOrderBy; /* The ORDER BY clause */
- int nOrderBy; /* Number of terms in the ORDER BY clause */
- int *aPermute; /* Mapping from ORDER BY terms to result set columns */
- #ifndef SQLITE_OMIT_EXPLAIN
- int iSub1; /* EQP id of left-hand query */
- int iSub2; /* EQP id of right-hand query */
- #endif
- assert( p->pOrderBy!=0 );
- assert( pKeyDup==0 ); /* "Managed" code needs this. Ticket #3382. */
- db = pParse->db;
- v = pParse->pVdbe;
- assert( v!=0 ); /* Already thrown the error if VDBE alloc failed */
- labelEnd = sqlite3VdbeMakeLabel(v);
- labelCmpr = sqlite3VdbeMakeLabel(v);
- /* Patch up the ORDER BY clause
- */
- op = p->op;
- pPrior = p->pPrior;
- assert( pPrior->pOrderBy==0 );
- pOrderBy = p->pOrderBy;
- assert( pOrderBy );
- nOrderBy = pOrderBy->nExpr;
- /* For operators other than UNION ALL we have to make sure that
- ** the ORDER BY clause covers every term of the result set. Add
- ** terms to the ORDER BY clause as necessary.
- */
- if( op!=TK_ALL ){
- for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
- struct ExprList_item *pItem;
- for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
- assert( pItem->iOrderByCol>0 );
- if( pItem->iOrderByCol==i ) break;
- }
- if( j==nOrderBy ){
- Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
- if( pNew==0 ) return SQLITE_NOMEM;
- pNew->flags |= EP_IntValue;
- pNew->u.iValue = i;
- pOrderBy = sqlite3ExprListAppend(pParse, pOrderBy, pNew);
- if( pOrderBy ) pOrderBy->a[nOrderBy++].iOrderByCol = (u16)i;
- }
- }
- }
- /* Compute the comparison permutation and keyinfo that is used with
- ** the permutation used to determine if the next
- ** row of results comes from selectA or selectB. Also add explicit
- ** collations to the ORDER BY clause terms so that when the subqueries
- ** to the right and the left are evaluated, they use the correct
- ** collation.
- */
- aPermute = sqlite3DbMallocRaw(db, sizeof(int)*nOrderBy);
- if( aPermute ){
- struct ExprList_item *pItem;
- for(i=0, pItem=pOrderBy->a; i<nOrderBy; i++, pItem++){
- assert( pItem->iOrderByCol>0 && pItem->iOrderByCol<=p->pEList->nExpr );
- aPermute[i] = pItem->iOrderByCol - 1;
- }
- pKeyMerge = sqlite3KeyInfoAlloc(db, nOrderBy);
- if( pKeyMerge ){
- for(i=0; i<nOrderBy; i++){
- CollSeq *pColl;
- Expr *pTerm = pOrderBy->a[i].pExpr;
- if( pTerm->flags & EP_Collate ){
- pColl = sqlite3ExprCollSeq(pParse, pTerm);
- }else{
- pColl = multiSelectCollSeq(pParse, p, aPermute[i]);
- if( pColl==0 ) pColl = db->pDfltColl;
- pOrderBy->a[i].pExpr =
- sqlite3ExprAddCollateString(pParse, pTerm, pColl->zName);
- }
- pKeyMerge->aColl[i] = pColl;
- pKeyMerge->aSortOrder[i] = pOrderBy->a[i].sortOrder;
- }
- }
- }else{
- pKeyMerge = 0;
- }
- /* Reattach the ORDER BY clause to the query.
- */
- p->pOrderBy = pOrderBy;
- pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
- /* Allocate a range of temporary registers and the KeyInfo needed
- ** for the logic that removes duplicate result rows when the
- ** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
- */
- if( op==TK_ALL ){
- regPrev = 0;
- }else{
- int nExpr = p->pEList->nExpr;
- assert( nOrderBy>=nExpr || db->mallocFailed );
- regPrev = pParse->nMem+1;
- pParse->nMem += nExpr+1;
- sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
- pKeyDup = sqlite3KeyInfoAlloc(db, nExpr);
- if( pKeyDup ){
- for(i=0; i<nExpr; i++){
- pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
- pKeyDup->aSortOrder[i] = 0;
- }
- }
- }
-
- /* Separate the left and the right query from one another
- */
- p->pPrior = 0;
- sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
- if( pPrior->pPrior==0 ){
- sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
- }
- /* Compute the limit registers */
- computeLimitRegisters(pParse, p, labelEnd);
- if( p->iLimit && op==TK_ALL ){
- regLimitA = ++pParse->nMem;
- regLimitB = ++pParse->nMem;
- sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
- regLimitA);
- sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
- }else{
- regLimitA = regLimitB = 0;
- }
- sqlite3ExprDelete(db, p->pLimit);
- p->pLimit = 0;
- sqlite3ExprDelete(db, p->pOffset);
- p->pOffset = 0;
- regAddrA = ++pParse->nMem;
- regEofA = ++pParse->nMem;
- regAddrB = ++pParse->nMem;
- regEofB = ++pParse->nMem;
- regOutA = ++pParse->nMem;
- regOutB = ++pParse->nMem;
- sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
- sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);
- /* Jump past the various subroutines and coroutines to the main
- ** merge loop
- */
- j1 = sqlite3VdbeAddOp0(v, OP_Goto);
- addrSelectA = sqlite3VdbeCurrentAddr(v);
- /* Generate a coroutine to evaluate the SELECT statement to the
- ** left of the compound operator - the "A" select.
- */
- VdbeNoopComment((v, "Begin coroutine for left SELECT"));
- pPrior->iLimit = regLimitA;
- explainSetInteger(iSub1, pParse->iNextSelectId);
- sqlite3Select(pParse, pPrior, &destA);
- sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
- sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
- VdbeNoopComment((v, "End coroutine for left SELECT"));
- /* Generate a coroutine to evaluate the SELECT statement on
- ** the right - the "B" select
- */
- addrSelectB = sqlite3VdbeCurrentAddr(v);
- VdbeNoopComment((v, "Begin coroutine for right SELECT"));
- savedLimit = p->iLimit;
- savedOffset = p->iOffset;
- p->iLimit = regLimitB;
- p->iOffset = 0;
- explainSetInteger(iSub2, pParse->iNextSelectId);
- sqlite3Select(pParse, p, &destB);
- p->iLimit = savedLimit;
- p->iOffset = savedOffset;
- sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
- sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
- VdbeNoopComment((v, "End coroutine for right SELECT"));
- /* Generate a subroutine that outputs the current row of the A
- ** select as the next output row of the compound select.
- */
- VdbeNoopComment((v, "Output routine for A"));
- addrOutA = generateOutputSubroutine(pParse,
- p, &destA, pDest, regOutA,
- regPrev, pKeyDup, P4_KEYINFO_HANDOFF, labelEnd);
-
- /* Generate a subroutine that outputs the current row of the B
- ** select as the next output row of the compound select.
- */
- if( op==TK_ALL || op==TK_UNION ){
- VdbeNoopComment((v, "Output routine for B"));
- addrOutB = generateOutputSubroutine(pParse,
- p, &destB, pDest, regOutB,
- regPrev, pKeyDup, P4_KEYINFO_STATIC, labelEnd);
- }
- /* Generate a subroutine to run when the results from select A
- ** are exhausted and only data in select B remains.
- */
- VdbeNoopComment((v, "eof-A subroutine"));
- if( op==TK_EXCEPT || op==TK_INTERSECT ){
- addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
- }else{
- addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
- sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
- sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
- sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
- p->nSelectRow += pPrior->nSelectRow;
- }
- /* Generate a subroutine to run when the results from select B
- ** are exhausted and only data in select A remains.
- */
- if( op==TK_INTERSECT ){
- addrEofB = addrEofA;
- if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
- }else{
- VdbeNoopComment((v, "eof-B subroutine"));
- addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
- sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
- sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
- sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
- }
- /* Generate code to handle the case of A<B
- */
- VdbeNoopComment((v, "A-lt-B subroutine"));
- addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
- sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
- sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
- sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
- /* Generate code to handle the case of A==B
- */
- if( op==TK_ALL ){
- addrAeqB = addrAltB;
- }else if( op==TK_INTERSECT ){
- addrAeqB = addrAltB;
- addrAltB++;
- }else{
- VdbeNoopComment((v, "A-eq-B subroutine"));
- addrAeqB =
- sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
- sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
- sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
- }
- /* Generate code to handle the case of A>B
- */
- VdbeNoopComment((v, "A-gt-B subroutine"));
- addrAgtB = sqlite3VdbeCurrentAddr(v);
- if( op==TK_ALL || op==TK_UNION ){
- sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
- }
- sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
- sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
- sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
- /* This code runs once to initialize everything.
- */
- sqlite3VdbeJumpHere(v, j1);
- sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
- sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
- sqlite3VdbeAddOp2(v, OP_Gosub, regAddrA, addrSelectA);
- sqlite3VdbeAddOp2(v, OP_Gosub, regAddrB, addrSelectB);
- sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
- sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
- /* Implement the main merge loop
- */
- sqlite3VdbeResolveLabel(v, labelCmpr);
- sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
- sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
- (char*)pKeyMerge, P4_KEYINFO_HANDOFF);
- sqlite3VdbeChangeP5(v, OPFLAG_PERMUTE);
- sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);
- /* Jump to the this point in order to terminate the query.
- */
- sqlite3VdbeResolveLabel(v, labelEnd);
- /* Set the number of output columns
- */
- if( pDest->eDest==SRT_Output ){
- Select *pFirst = pPrior;
- while( pFirst->pPrior ) pFirst = pFirst->pPrior;
- generateColumnNames(pParse, 0, pFirst->pEList);
- }
- /* Reassembly the compound query so that it will be freed correctly
- ** by the calling function */
- if( p->pPrior ){
- sqlite3SelectDelete(db, p->pPrior);
- }
- p->pPrior = pPrior;
- /*** TBD: Insert subroutine calls to close cursors on incomplete
- **** subqueries ****/
- explainComposite(pParse, p->op, iSub1, iSub2, 0);
- return SQLITE_OK;
- }
- #endif
- #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
- /* Forward Declarations */
- static void substExprList(sqlite3*, ExprList*, int, ExprList*);
- static void substSelect(sqlite3*, Select *, int, ExprList *);
- /*
- ** Scan through the expression pExpr. Replace every reference to
- ** a column in table number iTable with a copy of the iColumn-th
- ** entry in pEList. (But leave references to the ROWID column
- ** unchanged.)
- **
- ** This routine is part of the flattening procedure. A subquery
- ** whose result set is defined by pEList appears as entry in the
- ** FROM clause of a SELECT such that the VDBE cursor assigned to that
- ** FORM clause entry is iTable. This routine make the necessary
- ** changes to pExpr so that it refers directly to the source table
- ** of the subquery rather the result set of the subquery.
- */
- static Expr *substExpr(
- sqlite3 *db, /* Report malloc errors to this connection */
- Expr *pExpr, /* Expr in which substitution occurs */
- int iTable, /* Table to be substituted */
- ExprList *pEList /* Substitute expressions */
- ){
- if( pExpr==0 ) return 0;
- if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
- if( pExpr->iColumn<0 ){
- pExpr->op = TK_NULL;
- }else{
- Expr *pNew;
- assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
- assert( pExpr->pLeft==0 && pExpr->pRight==0 );
- pNew = sqlite3ExprDup(db, pEList->a[pExpr->iColumn].pExpr, 0);
- sqlite3ExprDelete(db, pExpr);
- pExpr = pNew;
- }
- }else{
- pExpr->pLeft = substExpr(db, pExpr->pLeft, iTable, pEList);
- pExpr->pRight = substExpr(db, pExpr->pRight, iTable, pEList);
- if( ExprHasProperty(pExpr, EP_xIsSelect) ){
- substSelect(db, pExpr->x.pSelect, iTable, pEList);
- }else{
- substExprList(db, pExpr->x.pList, iTable, pEList);
- }
- }
- return pExpr;
- }
- static void substExprList(
- sqlite3 *db, /* Report malloc errors here */
- ExprList *pList, /* List to scan and in which to make substitutes */
- int iTable, /* Table to be substituted */
- ExprList *pEList /* Substitute values */
- ){
- int i;
- if( pList==0 ) return;
- for(i=0; i<pList->nExpr; i++){
- pList->a[i].pExpr = substExpr(db, pList->a[i].pExpr, iTable, pEList);
- }
- }
- static void substSelect(
- sqlite3 *db, /* Report malloc errors here */
- Select *p, /* SELECT statement in which to make substitutions */
- int iTable, /* Table to be replaced */
- ExprList *pEList /* Substitute values */
- ){
- SrcList *pSrc;
- struct SrcList_item *pItem;
- int i;
- if( !p ) return;
- substExprList(db, p->pEList, iTable, pEList);
- substExprList(db, p->pGroupBy, iTable, pEList);
- substExprList(db, p->pOrderBy, iTable, pEList);
- p->pHaving = substExpr(db, p->pHaving, iTable, pEList);
- p->pWhere = substExpr(db, p->pWhere, iTable, pEList);
- substSelect(db, p->pPrior, iTable, pEList);
- pSrc = p->pSrc;
- assert( pSrc ); /* Even for (SELECT 1) we have: pSrc!=0 but pSrc->nSrc==0 */
- if( ALWAYS(pSrc) ){
- for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
- substSelect(db, pItem->pSelect, iTable, pEList);
- }
- }
- }
- #endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
- #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
- /*
- ** This routine attempts to flatten subqueries as a performance optimization.
- ** This routine returns 1 if it makes changes and 0 if no flattening occurs.
- **
- ** To understand the concept of flattening, consider the following
- ** query:
- **
- ** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
- **
- ** The default way of implementing this query is to execute the
- ** subquery first and store the results in a temporary table, then
- ** run the outer query on that temporary table. This requires two
- ** passes over the data. Furthermore, because the temporary table
- ** has no indices, the WHERE clause on the outer query cannot be
- ** optimized.
- **
- ** This routine attempts to rewrite queries such as the above into
- ** a single flat select, like this:
- **
- ** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
- **
- ** The code generated for this simpification gives the same result
- ** but only has to scan the data once. And because indices might
- ** exist on the table t1, a complete scan of the data might be
- ** avoided.
- **
- ** Flattening is only attempted if all of the following are true:
- **
- ** (1) The subquery and the outer query do not both use aggregates.
- **
- ** (2) The subquery is not an aggregate or the outer query is not a join.
- **
- ** (3) The subquery is not the right operand of a left outer join
- ** (Originally ticket #306. Strengthened by ticket #3300)
- **
- ** (4) The subquery is not DISTINCT.
- **
- ** (**) At one point restrictions (4) and (5) defined a subset of DISTINCT
- ** sub-queries that were excluded from this optimization. Restriction
- ** (4) has since been expanded to exclude all DISTINCT subqueries.
- **
- ** (6) The subquery does not use aggregates or the outer query is not
- ** DISTINCT.
- **
- ** (7) The subquery has a FROM clause. TODO: For subqueries without
- ** A FROM clause, consider adding a FROM close with the special
- ** table sqlite_once that consists of a single row containing a
- ** single NULL.
- **
- ** (8) The subquery does not use LIMIT or the outer query is not a join.
- **
- ** (9) The subquery does not use LIMIT or the outer query does not use
- ** aggregates.
- **
- ** (10) The subquery does not use aggregates or the outer query does not
- ** use LIMIT.
- **
- ** (11) The subquery and the outer query do not both have ORDER BY clauses.
- **
- ** (**) Not implemented. Subsumed into restriction (3). Was previously
- ** a separate restriction deriving from ticket #350.
- **
- ** (13) The subquery and outer query do not both use LIMIT.
- **
- ** (14) The subquery does not use OFFSET.
- **
- ** (15) The outer query is not part of a compound select or the
- ** subquery does not have a LIMIT clause.
- ** (See ticket #2339 and ticket [02a8e81d44]).
- **
- ** (16) The outer query is not an aggregate or the subquery does
- ** not contain ORDER BY. (Ticket #2942) This used to not matter
- ** until we introduced the group_concat() function.
- **
- ** (17) The sub-query is not a compound select, or it is a UNION ALL
- ** compound clause made up entirely of non-aggregate queries, and
- ** the parent query:
- **
- ** * is not itself part of a compound select,
- ** * is not an aggregate or DISTINCT query, and
- ** * is not a join
- **
- ** The parent and sub-query may contain WHERE clauses. Subject to
- ** rules (11), (13) and (14), they may also contain ORDER BY,
- ** LIMIT and OFFSET clauses. The subquery cannot use any compound
- ** operator other than UNION ALL because all the other compound
- ** operators have an implied DISTINCT which is disallowed by
- ** restriction (4).
- **
- ** Also, each component of the sub-query must return the same number
- ** of result columns. This is actually a requirement for any compound
- ** SELECT statement, but all the code here does is make sure that no
- ** such (illegal) sub-query is flattened. The caller will detect the
- ** syntax error and return a detailed message.
- **
- ** (18) If the sub-query is a compound select, then all terms of the
- ** ORDER by clause of the parent must be simple references to
- ** columns of the sub-query.
- **
- ** (19) The subquery does not use LIMIT or the outer query does not
- ** have a WHERE clause.
- **
- ** (20) If the sub-query is a compound select, then it must not use
- ** an ORDER BY clause. Ticket #3773. We could relax this constraint
- ** somewhat by saying that the terms of the ORDER BY clause must
- ** appear as unmodified result columns in the outer query. But we
- ** have other optimizations in mind to deal with that case.
- **
- ** (21) The subquery does not use LIMIT or the outer query is not
- ** DISTINCT. (See ticket [752e1646fc]).
- **
- ** In this routine, the "p" parameter is a pointer to the outer query.
- ** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
- ** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
- **
- ** If flattening is not attempted, this routine is a no-op and returns 0.
- ** If flattening is attempted this routine returns 1.
- **
- ** All of the expression analysis must occur on both the outer query and
- ** the subquery before this routine runs.
- */
- static int flattenSubquery(
- Parse *pParse, /* Parsing context */
- Select *p, /* The parent or outer SELECT statement */
- int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
- int isAgg, /* True if outer SELECT uses aggregate functions */
- int subqueryIsAgg /* True if the subquery uses aggregate functions */
- ){
- const char *zSavedAuthContext = pParse->zAuthContext;
- Select *pParent;
- Select *pSub; /* The inner query or "subquery" */
- Select *pSub1; /* Pointer to the rightmost select in sub-query */
- SrcList *pSrc; /* The FROM clause of the outer query */
- SrcList *pSubSrc; /* The FROM clause of the subquery */
- ExprList *pList; /* The result set of the outer query */
- int iParent; /* VDBE cursor number of the pSub result set temp table */
- int i; /* Loop counter */
- Expr *pWhere; /* The WHERE clause */
- struct SrcList_item *pSubitem; /* The subquery */
- sqlite3 *db = pParse->db;
- /* Check to see if flattening is permitted. Return 0 if not.
- */
- assert( p!=0 );
- assert( p->pPrior==0 ); /* Unable to flatten compound queries */
- if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0;
- pSrc = p->pSrc;
- assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
- pSubitem = &pSrc->a[iFrom];
- iParent = pSubitem->iCursor;
- pSub = pSubitem->pSelect;
- assert( pSub!=0 );
- if( isAgg && subqueryIsAgg ) return 0; /* Restriction (1) */
- if( subqueryIsAgg && pSrc->nSrc>1 ) return 0; /* Restriction (2) */
- pSubSrc = pSub->pSrc;
- assert( pSubSrc );
- /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
- ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
- ** because they could be computed at compile-time. But when LIMIT and OFFSET
- ** became arbitrary expressions, we were forced to add restrictions (13)
- ** and (14). */
- if( pSub->pLimit && p->pLimit ) return 0; /* Restriction (13) */
- if( pSub->pOffset ) return 0; /* Restriction (14) */
- if( p->pRightmost && pSub->pLimit ){
- return 0; /* Restriction (15) */
- }
- if( pSubSrc->nSrc==0 ) return 0; /* Restriction (7) */
- if( pSub->selFlags & SF_Distinct ) return 0; /* Restriction (5) */
- if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
- return 0; /* Restrictions (8)(9) */
- }
- if( (p->selFlags & SF_Distinct)!=0 && subqueryIsAgg ){
- return 0; /* Restriction (6) */
- }
- if( p->pOrderBy && pSub->pOrderBy ){
- return 0; /* Restriction (11) */
- }
- if( isAgg && pSub->pOrderBy ) return 0; /* Restriction (16) */
- if( pSub->pLimit && p->pWhere ) return 0; /* Restriction (19) */
- if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
- return 0; /* Restriction (21) */
- }
- /* OBSOLETE COMMENT 1:
- ** Restriction 3: If the subquery is a join, make sure the subquery is
- ** not used as the right operand of an outer join. Examples of why this
- ** is not allowed:
- **
- ** t1 LEFT OUTER JOIN (t2 JOIN t3)
- **
- ** If we flatten the above, we would get
- **
- ** (t1 LEFT OUTER JOIN t2) JOIN t3
- **
- ** which is not at all the same thing.
- **
- ** OBSOLETE COMMENT 2:
- ** Restriction 12: If the subquery is the right operand of a left outer
- ** join, make sure the subquery has no WHERE clause.
- ** An examples of why this is not allowed:
- **
- ** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
- **
- ** If we flatten the above, we would get
- **
- ** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
- **
- ** But the t2.x>0 test will always fail on a NULL row of t2, which
- ** effectively converts the OUTER JOIN into an INNER JOIN.
- **
- ** THIS OVERRIDES OBSOLETE COMMENTS 1 AND 2 ABOVE:
- ** Ticket #3300 shows that flattening the right term of a LEFT JOIN
- ** is fraught with danger. Best to avoid the whole thing. If the
- ** subquery is the right term of a LEFT JOIN, then do not flatten.
- */
- if( (pSubitem->jointype & JT_OUTER)!=0 ){
- return 0;
- }
- /* Restriction 17: If the sub-query is a compound SELECT, then it must
- ** use only the UNION ALL operator. And none of the simple select queries
- ** that make up the compound SELECT are allowed to be aggregate or distinct
- ** queries.
- */
- if( pSub->pPrior ){
- if( pSub->pOrderBy ){
- return 0; /* Restriction 20 */
- }
- if( isAgg || (p->selFlags & SF_Distinct)!=0 || pSrc->nSrc!=1 ){
- return 0;
- }
- for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
- testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
- testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
- assert( pSub->pSrc!=0 );
- if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0
- || (pSub1->pPrior && pSub1->op!=TK_ALL)
- || pSub1->pSrc->nSrc<1
- || pSub->pEList->nExpr!=pSub1->pEList->nExpr
- ){
- return 0;
- }
- testcase( pSub1->pSrc->nSrc>1 );
- }
- /* Restriction 18. */
- if( p->pOrderBy ){
- int ii;
- for(ii=0; ii<p->pOrderBy->nExpr; ii++){
- if( p->pOrderBy->a[ii].iOrderByCol==0 ) return 0;
- }
- }
- }
- /***** If we reach this point, flattening is permitted. *****/
- /* Authorize the subquery */
- pParse->zAuthContext = pSubitem->zName;
- TESTONLY(i =) sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
- testcase( i==SQLITE_DENY );
- pParse->zAuthContext = zSavedAuthContext;
- /* If the sub-query is a compound SELECT statement, then (by restrictions
- ** 17 and 18 above) it must be a UNION ALL and the parent query must
- ** be of the form:
- **
- ** SELECT <expr-list> FROM (<sub-query>) <where-clause>
- **
- ** followed by any ORDER BY, LIMIT and/or OFFSET clauses. This block
- ** creates N-1 copies of the parent query without any ORDER BY, LIMIT or
- ** OFFSET clauses and joins them to the left-hand-side of the original
- ** using UNION ALL operators. In this case N is the number of simple
- ** select statements in the compound sub-query.
- **
- ** Example:
- **
- ** SELECT a+1 FROM (
- ** SELECT x FROM tab
- ** UNION ALL
- ** SELECT y FROM tab
- ** UNION ALL
- ** SELECT abs(z*2) FROM tab2
- ** ) WHERE a!=5 ORDER BY 1
- **
- ** Transformed into:
- **
- ** SELECT x+1 FROM tab WHERE x+1!=5
- ** UNION ALL
- ** SELECT y+1 FROM tab WHERE y+1!=5
- ** UNION ALL
- ** SELECT abs(z*2)+1 FROM tab2 WHERE abs(z*2)+1!=5
- ** ORDER BY 1
- **
- ** We call this the "compound-subquery flattening".
- */
- for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){
- Select *pNew;
- ExprList *pOrderBy = p->pOrderBy;
- Expr *pLimit = p->pLimit;
- Expr *pOffset = p->pOffset;
- Select *pPrior = p->pPrior;
- p->pOrderBy = 0;
- p->pSrc = 0;
- p->pPrior = 0;
- p->pLimit = 0;
- p->pOffset = 0;
- pNew = sqlite3SelectDup(db, p, 0);
- p->pOffset = pOffset;
- p->pLimit = pLimit;
- p->pOrderBy = pOrderBy;
- p->pSrc = pSrc;
- p->op = TK_ALL;
- p->pRightmost = 0;
- if( pNew==0 ){
- pNew = pPrior;
- }else{
- pNew->pPrior = pPrior;
- pNew->pRightmost = 0;
- }
- p->pPrior = pNew;
- if( db->mallocFailed ) return 1;
- }
- /* Begin flattening the iFrom-th entry of the FROM clause
- ** in the outer query.
- */
- pSub = pSub1 = pSubitem->pSelect;
- /* Delete the transient table structure associated with the
- ** subquery
- */
- sqlite3DbFree(db, pSubitem->zDatabase);
- sqlite3DbFree(db, pSubitem->zName);
- sqlite3DbFree(db, pSubitem->zAlias);
- pSubitem->zDatabase = 0;
- pSubitem->zName = 0;
- pSubitem->zAlias = 0;
- pSubitem->pSelect = 0;
- /* Defer deleting the Table object associated with the
- ** subquery until code generation is
- ** complete, since there may still exist Expr.pTab entries that
- ** refer to the subquery even after flattening. Ticket #3346.
- **
- ** pSubitem->pTab is always non-NULL by test restrictions and tests above.
- */
- if( ALWAYS(pSubitem->pTab!=0) ){
- Table *pTabToDel = pSubitem->pTab;
- if( pTabToDel->nRef==1 ){
- Parse *pToplevel = sqlite3ParseToplevel(pParse);
- pTabToDel->pNextZombie = pToplevel->pZombieTab;
- pToplevel->pZombieTab = pTabToDel;
- }else{
- pTabToDel->nRef--;
- }
- pSubitem->pTab = 0;
- }
- /* The following loop runs once for each term in a compound-subquery
- ** flattening (as described above). If we are doing a different kind
- ** of flattening - a flattening other than a compound-subquery flattening -
- ** then this loop only runs once.
- **
- ** This loop moves all of the FROM elements of the subquery into the
- ** the FROM clause of the outer query. Before doing this, remember
- ** the cursor number for the original outer query FROM element in
- ** iParent. The iParent cursor will never be used. Subsequent code
- ** will scan expressions looking for iParent references and replace
- ** those references with expressions that resolve to the subquery FROM
- ** elements we are now copying in.
- */
- for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
- int nSubSrc;
- u8 jointype = 0;
- pSubSrc = pSub->pSrc; /* FROM clause of subquery */
- nSubSrc = pSubSrc->nSrc; /* Number of terms in subquery FROM clause */
- pSrc = pParent->pSrc; /* FROM clause of the outer query */
- if( pSrc ){
- assert( pParent==p ); /* First time through the loop */
- jointype = pSubitem->jointype;
- }else{
- assert( pParent!=p ); /* 2nd and subsequent times through the loop */
- pSrc = pParent->pSrc = sqlite3SrcListAppend(db, 0, 0, 0);
- if( pSrc==0 ){
- assert( db->mallocFailed );
- break;
- }
- }
- /* The subquery uses a single slot of the FROM clause of the outer
- ** query. If the subquery has more than one element in its FROM clause,
- ** then expand the outer query to make space for it to hold all elements
- ** of the subquery.
- **
- ** Example:
- **
- ** SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB;
- **
- ** The outer query has 3 slots in its FROM clause. One slot of the
- ** outer query (the middle slot) is used by the subquery. The next
- ** block of code will expand the out query to 4 slots. The middle
- ** slot is expanded to two slots in order to make space for the
- ** two elements in the FROM clause of the subquery.
- */
- if( nSubSrc>1 ){
- pParent->pSrc = pSrc = sqlite3SrcListEnlarge(db, pSrc, nSubSrc-1,iFrom+1);
- if( db->mallocFailed ){
- break;
- }
- }
- /* Transfer the FROM clause terms from the subquery into the
- ** outer query.
- */
- for(i=0; i<nSubSrc; i++){
- sqlite3IdListDelete(db, pSrc->a[i+iFrom].pUsing);
- pSrc->a[i+iFrom] = pSubSrc->a[i];
- memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
- }
- pSrc->a[iFrom].jointype = jointype;
-
- /* Now begin substituting subquery result set expressions for
- ** references to the iParent in the outer query.
- **
- ** Example:
- **
- ** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
- ** \ \_____________ subquery __________/ /
- ** \_____________________ outer query ______________________________/
- **
- ** We look at every expression in the outer query and every place we see
- ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
- */
- pList = pParent->pEList;
- for(i=0; i<pList->nExpr; i++){
- if( pList->a[i].zName==0 ){
- char *zName = sqlite3DbStrDup(db, pList->a[i].zSpan);
- sqlite3Dequote(zName);
- pList->a[i].zName = zName;
- }
- }
- substExprList(db, pParent->pEList, iParent, pSub->pEList);
- if( isAgg ){
- substExprList(db, pParent->pGroupBy, iParent, pSub->pEList);
- pParent->pHaving = substExpr(db, pParent->pHaving, iParent, pSub->pEList);
- }
- if( pSub->pOrderBy ){
- assert( pParent->pOrderBy==0 );
- pParent->pOrderBy = pSub->pOrderBy;
- pSub->pOrderBy = 0;
- }else if( pParent->pOrderBy ){
- substExprList(db, pParent->pOrderBy, iParent, pSub->pEList);
- }
- if( pSub->pWhere ){
- pWhere = sqlite3ExprDup(db, pSub->pWhere, 0);
- }else{
- pWhere = 0;
- }
- if( subqueryIsAgg ){
- assert( pParent->pHaving==0 );
- pParent->pHaving = pParent->pWhere;
- pParent->pWhere = pWhere;
- pParent->pHaving = substExpr(db, pParent->pHaving, iParent, pSub->pEList);
- pParent->pHaving = sqlite3ExprAnd(db, pParent->pHaving,
- sqlite3ExprDup(db, pSub->pHaving, 0));
- assert( pParent->pGroupBy==0 );
- pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy, 0);
- }else{
- pParent->pWhere = substExpr(db, pParent->pWhere, iParent, pSub->pEList);
- pParent->pWhere = sqlite3ExprAnd(db, pParent->pWhere, pWhere);
- }
-
- /* The flattened query is distinct if either the inner or the
- ** outer query is distinct.
- */
- pParent->selFlags |= pSub->selFlags & SF_Distinct;
-
- /*
- ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
- **
- ** One is tempted to try to add a and b to combine the limits. But this
- ** does not work if either limit is negative.
- */
- if( pSub->pLimit ){
- pParent->pLimit = pSub->pLimit;
- pSub->pLimit = 0;
- }
- }
- /* Finially, delete what is left of the subquery and return
- ** success.
- */
- sqlite3SelectDelete(db, pSub1);
- return 1;
- }
- #endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
- /*
- ** Based on the contents of the AggInfo structure indicated by the first
- ** argument, this function checks if the following are true:
- **
- ** * the query contains just a single aggregate function,
- ** * the aggregate function is either min() or max(), and
- ** * the argument to the aggregate function is a column value.
- **
- ** If all of the above are true, then WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX
- ** is returned as appropriate. Also, *ppMinMax is set to point to the
- ** list of arguments passed to the aggregate before returning.
- **
- ** Or, if the conditions above are not met, *ppMinMax is set to 0 and
- ** WHERE_ORDERBY_NORMAL is returned.
- */
- static u8 minMaxQuery(AggInfo *pAggInfo, ExprList **ppMinMax){
- int eRet = WHERE_ORDERBY_NORMAL; /* Return value */
- *ppMinMax = 0;
- if( pAggInfo->nFunc==1 ){
- Expr *pExpr = pAggInfo->aFunc[0].pExpr; /* Aggregate function */
- ExprList *pEList = pExpr->x.pList; /* Arguments to agg function */
- assert( pExpr->op==TK_AGG_FUNCTION );
- if( pEList && pEList->nExpr==1 && pEList->a[0].pExpr->op==TK_AGG_COLUMN ){
- const char *zFunc = pExpr->u.zToken;
- if( sqlite3StrICmp(zFunc, "min")==0 ){
- eRet = WHERE_ORDERBY_MIN;
- *ppMinMax = pEList;
- }else if( sqlite3StrICmp(zFunc, "max")==0 ){
- eRet = WHERE_ORDERBY_MAX;
- *ppMinMax = pEList;
- }
- }
- }
- assert( *ppMinMax==0 || (*ppMinMax)->nExpr==1 );
- return eRet;
- }
- /*
- ** The select statement passed as the first argument is an aggregate query.
- ** The second argment is the associated aggregate-info object. This
- ** function tests if the SELECT is of the form:
- **
- ** SELECT count(*) FROM <tbl>
- **
- ** where table is a database table, not a sub-select or view. If the query
- ** does match this pattern, then a pointer to the Table object representing
- ** <tbl> is returned. Otherwise, 0 is returned.
- */
- static Table *isSimpleCount(Select *p, AggInfo *pAggInfo){
- Table *pTab;
- Expr *pExpr;
- assert( !p->pGroupBy );
- if( p->pWhere || p->pEList->nExpr!=1
- || p->pSrc->nSrc!=1 || p->pSrc->a[0].pSelect
- ){
- return 0;
- }
- pTab = p->pSrc->a[0].pTab;
- pExpr = p->pEList->a[0].pExpr;
- assert( pTab && !pTab->pSelect && pExpr );
- if( IsVirtual(pTab) ) return 0;
- if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
- if( NEVER(pAggInfo->nFunc==0) ) return 0;
- if( (pAggInfo->aFunc[0].pFunc->funcFlags&SQLITE_FUNC_COUNT)==0 ) return 0;
- if( pExpr->flags&EP_Distinct ) return 0;
- return pTab;
- }
- /*
- ** If the source-list item passed as an argument was augmented with an
- ** INDEXED BY clause, then try to locate the specified index. If there
- ** was such a clause and the named index cannot be found, return
- ** SQLITE_ERROR and leave an error in pParse. Otherwise, populate
- ** pFrom->pIndex and return SQLITE_OK.
- */
- int sqlite3IndexedByLookup(Parse *pParse, struct SrcList_item *pFrom){
- if( pFrom->pTab && pFrom->zIndex ){
- Table *pTab = pFrom->pTab;
- char *zIndex = pFrom->zIndex;
- Index *pIdx;
- for(pIdx=pTab->pIndex;
- pIdx && sqlite3StrICmp(pIdx->zName, zIndex);
- pIdx=pIdx->pNext
- );
- if( !pIdx ){
- sqlite3ErrorMsg(pParse, "no such index: %s", zIndex, 0);
- pParse->checkSchema = 1;
- return SQLITE_ERROR;
- }
- pFrom->pIndex = pIdx;
- }
- return SQLITE_OK;
- }
- /*
- ** Detect compound SELECT statements that use an ORDER BY clause with
- ** an alternative collating sequence.
- **
- ** SELECT ... FROM t1 EXCEPT SELECT ... FROM t2 ORDER BY .. COLLATE ...
- **
- ** These are rewritten as a subquery:
- **
- ** SELECT * FROM (SELECT ... FROM t1 EXCEPT SELECT ... FROM t2)
- ** ORDER BY ... COLLATE ...
- **
- ** This transformation is necessary because the multiSelectOrderBy() routine
- ** above that generates the code for a compound SELECT with an ORDER BY clause
- ** uses a merge algorithm that requires the same collating sequence on the
- ** result columns as on the ORDER BY clause. See ticket
- ** http://www.sqlite.org/src/info/6709574d2a
- **
- ** This transformation is only needed for EXCEPT, INTERSECT, and UNION.
- ** The UNION ALL operator works fine with multiSelectOrderBy() even when
- ** there are COLLATE terms in the ORDER BY.
- */
- static int convertCompoundSelectToSubquery(Walker *pWalker, Select *p){
- int i;
- Select *pNew;
- Select *pX;
- sqlite3 *db;
- struct ExprList_item *a;
- SrcList *pNewSrc;
- Parse *pParse;
- Token dummy;
- if( p->pPrior==0 ) return WRC_Continue;
- if( p->pOrderBy==0 ) return WRC_Continue;
- for(pX=p; pX && (pX->op==TK_ALL || pX->op==TK_SELECT); pX=pX->pPrior){}
- if( pX==0 ) return WRC_Continue;
- a = p->pOrderBy->a;
- for(i=p->pOrderBy->nExpr-1; i>=0; i--){
- if( a[i].pExpr->flags & EP_Collate ) break;
- }
- if( i<0 ) return WRC_Continue;
- /* If we reach this point, that means the transformation is required. */
- pParse = pWalker->pParse;
- db = pParse->db;
- pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
- if( pNew==0 ) return WRC_Abort;
- memset(&dummy, 0, sizeof(dummy));
- pNewSrc = sqlite3SrcListAppendFromTerm(pParse,0,0,0,&dummy,pNew,0,0);
- if( pNewSrc==0 ) return WRC_Abort;
- *pNew = *p;
- p->pSrc = pNewSrc;
- p->pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ALL, 0));
- p->op = TK_SELECT;
- p->pWhere = 0;
- pNew->pGroupBy = 0;
- pNew->pHaving = 0;
- pNew->pOrderBy = 0;
- p->pPrior = 0;
- pNew->pLimit = 0;
- pNew->pOffset = 0;
- return WRC_Continue;
- }
- /*
- ** This routine is a Walker callback for "expanding" a SELECT statement.
- ** "Expanding" means to do the following:
- **
- ** (1) Make sure VDBE cursor numbers have been assigned to every
- ** element of the FROM clause.
- **
- ** (2) Fill in the pTabList->a[].pTab fields in the SrcList that
- ** defines FROM clause. When views appear in the FROM clause,
- ** fill pTabList->a[].pSelect with a copy of the SELECT statement
- ** that implements the view. A copy is made of the view's SELECT
- ** statement so that we can freely modify or delete that statement
- ** without worrying about messing up the presistent representation
- ** of the view.
- **
- ** (3) Add terms to the WHERE clause to accomodate the NATURAL keyword
- ** on joins and the ON and USING clause of joins.
- **
- ** (4) Scan the list of columns in the result set (pEList) looking
- ** for instances of the "*" operator or the TABLE.* operator.
- ** If found, expand each "*" to be every column in every table
- ** and TABLE.* to be every column in TABLE.
- **
- */
- static int selectExpander(Walker *pWalker, Select *p){
- Parse *pParse = pWalker->pParse;
- int i, j, k;
- SrcList *pTabList;
- ExprList *pEList;
- struct SrcList_item *pFrom;
- sqlite3 *db = pParse->db;
- Expr *pE, *pRight, *pExpr;
- u16 selFlags = p->selFlags;
- p->selFlags |= SF_Expanded;
- if( db->mallocFailed ){
- return WRC_Abort;
- }
- if( NEVER(p->pSrc==0) || (selFlags & SF_Expanded)!=0 ){
- return WRC_Prune;
- }
- pTabList = p->pSrc;
- pEList = p->pEList;
- /* Make sure cursor numbers have been assigned to all entries in
- ** the FROM clause of the SELECT statement.
- */
- sqlite3SrcListAssignCursors(pParse, pTabList);
- /* Look up every table named in the FROM clause of the select. If
- ** an entry of the FROM clause is a subquery instead of a table or view,
- ** then create a transient table structure to describe the subquery.
- */
- for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
- Table *pTab;
- if( pFrom->pTab!=0 ){
- /* This statement has already been prepared. There is no need
- ** to go further. */
- assert( i==0 );
- return WRC_Prune;
- }
- if( pFrom->zName==0 ){
- #ifndef SQLITE_OMIT_SUBQUERY
- Select *pSel = pFrom->pSelect;
- /* A sub-query in the FROM clause of a SELECT */
- assert( pSel!=0 );
- assert( pFrom->pTab==0 );
- sqlite3WalkSelect(pWalker, pSel);
- pFrom->pTab = pTab = sqlite3DbMallocZero(db, sizeof(Table));
- if( pTab==0 ) return WRC_Abort;
- pTab->nRef = 1;
- pTab->zName = sqlite3MPrintf(db, "sqlite_sq_%p", (void*)pTab);
- while( pSel->pPrior ){ pSel = pSel->pPrior; }
- selectColumnsFromExprList(pParse, pSel->pEList, &pTab->nCol, &pTab->aCol);
- pTab->iPKey = -1;
- pTab->nRowEst = 1048576;
- pTab->tabFlags |= TF_Ephemeral;
- #endif
- }else{
- /* An ordinary table or view name in the FROM clause */
- assert( pFrom->pTab==0 );
- pFrom->pTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom);
- if( pTab==0 ) return WRC_Abort;
- if( pTab->nRef==0xffff ){
- sqlite3ErrorMsg(pParse, "too many references to \"%s\": max 65535",
- pTab->zName);
- pFrom->pTab = 0;
- return WRC_Abort;
- }
- pTab->nRef++;
- #if !defined(SQLITE_OMIT_VIEW) || !defined (SQLITE_OMIT_VIRTUALTABLE)
- if( pTab->pSelect || IsVirtual(pTab) ){
- /* We reach here if the named table is a really a view */
- if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
- assert( pFrom->pSelect==0 );
- pFrom->pSelect = sqlite3SelectDup(db, pTab->pSelect, 0);
- sqlite3WalkSelect(pWalker, pFrom->pSelect);
- }
- #endif
- }
- /* Locate the index named by the INDEXED BY clause, if any. */
- if( sqlite3IndexedByLookup(pParse, pFrom) ){
- return WRC_Abort;
- }
- }
- /* Process NATURAL keywords, and ON and USING clauses of joins.
- */
- if( db->mallocFailed || sqliteProcessJoin(pParse, p) ){
- return WRC_Abort;
- }
- /* For every "*" that occurs in the column list, insert the names of
- ** all columns in all tables. And for every TABLE.* insert the names
- ** of all columns in TABLE. The parser inserted a special expression
- ** with the TK_ALL operator for each "*" that it found in the column list.
- ** The following code just has to locate the TK_ALL expressions and expand
- ** each one to the list of all columns in all tables.
- **
- ** The first loop just checks to see if there are any "*" operators
- ** that need expanding.
- */
- for(k=0; k<pEList->nExpr; k++){
- pE = pEList->a[k].pExpr;
- if( pE->op==TK_ALL ) break;
- assert( pE->op!=TK_DOT || pE->pRight!=0 );
- assert( pE->op!=TK_DOT || (pE->pLeft!=0 && pE->pLeft->op==TK_ID) );
- if( pE->op==TK_DOT && pE->pRight->op==TK_ALL ) break;
- }
- if( k<pEList->nExpr ){
- /*
- ** If we get here it means the result set contains one or more "*"
- ** operators that need to be expanded. Loop through each expression
- ** in the result set and expand them one by one.
- */
- struct ExprList_item *a = pEList->a;
- ExprList *pNew = 0;
- int flags = pParse->db->flags;
- int longNames = (flags & SQLITE_FullColNames)!=0
- && (flags & SQLITE_ShortColNames)==0;
- /* When processing FROM-clause subqueries, it is always the case
- ** that full_column_names=OFF and short_column_names=ON. The
- ** sqlite3ResultSetOfSelect() routine makes it so. */
- assert( (p->selFlags & SF_NestedFrom)==0
- || ((flags & SQLITE_FullColNames)==0 &&
- (flags & SQLITE_ShortColNames)!=0) );
- for(k=0; k<pEList->nExpr; k++){
- pE = a[k].pExpr;
- pRight = pE->pRight;
- assert( pE->op!=TK_DOT || pRight!=0 );
- if( pE->op!=TK_ALL && (pE->op!=TK_DOT || pRight->op!=TK_ALL) ){
- /* This particular expression does not need to be expanded.
- */
- pNew = sqlite3ExprListAppend(pParse, pNew, a[k].pExpr);
- if( pNew ){
- pNew->a[pNew->nExpr-1].zName = a[k].zName;
- pNew->a[pNew->nExpr-1].zSpan = a[k].zSpan;
- a[k].zName = 0;
- a[k].zSpan = 0;
- }
- a[k].pExpr = 0;
- }else{
- /* This expression is a "*" or a "TABLE.*" and needs to be
- ** expanded. */
- int tableSeen = 0; /* Set to 1 when TABLE matches */
- char *zTName = 0; /* text of name of TABLE */
- if( pE->op==TK_DOT ){
- assert( pE->pLeft!=0 );
- assert( !ExprHasProperty(pE->pLeft, EP_IntValue) );
- zTName = pE->pLeft->u.zToken;
- }
- for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
- Table *pTab = pFrom->pTab;
- Select *pSub = pFrom->pSelect;
- char *zTabName = pFrom->zAlias;
- const char *zSchemaName = 0;
- int iDb;
- if( zTabName==0 ){
- zTabName = pTab->zName;
- }
- if( db->mallocFailed ) break;
- if( pSub==0 || (pSub->selFlags & SF_NestedFrom)==0 ){
- pSub = 0;
- if( zTName && sqlite3StrICmp(zTName, zTabName)!=0 ){
- continue;
- }
- iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
- zSchemaName = iDb>=0 ? db->aDb[iDb].zName : "*";
- }
- for(j=0; j<pTab->nCol; j++){
- char *zName = pTab->aCol[j].zName;
- char *zColname; /* The computed column name */
- char *zToFree; /* Malloced string that needs to be freed */
- Token sColname; /* Computed column name as a token */
- assert( zName );
- if( zTName && pSub
- && sqlite3MatchSpanName(pSub->pEList->a[j].zSpan, 0, zTName, 0)==0
- ){
- continue;
- }
- /* If a column is marked as 'hidden' (currently only possible
- ** for virtual tables), do not include it in the expanded
- ** result-set list.
- */
- if( IsHiddenColumn(&pTab->aCol[j]) ){
- assert(IsVirtual(pTab));
- continue;
- }
- tableSeen = 1;
- if( i>0 && zTName==0 ){
- if( (pFrom->jointype & JT_NATURAL)!=0
- && tableAndColumnIndex(pTabList, i, zName, 0, 0)
- ){
- /* In a NATURAL join, omit the join columns from the
- ** table to the right of the join */
- continue;
- }
- if( sqlite3IdListIndex(pFrom->pUsing, zName)>=0 ){
- /* In a join with a USING clause, omit columns in the
- ** using clause from the table on the right. */
- continue;
- }
- }
- pRight = sqlite3Expr(db, TK_ID, zName);
- zColname = zName;
- zToFree = 0;
- if( longNames || pTabList->nSrc>1 ){
- Expr *pLeft;
- pLeft = sqlite3Expr(db, TK_ID, zTabName);
- pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
- if( zSchemaName ){
- pLeft = sqlite3Expr(db, TK_ID, zSchemaName);
- pExpr = sqlite3PExpr(pParse, TK_DOT, pLeft, pExpr, 0);
- }
- if( longNames ){
- zColname = sqlite3MPrintf(db, "%s.%s", zTabName, zName);
- zToFree = zColname;
- }
- }else{
- pExpr = pRight;
- }
- pNew = sqlite3ExprListAppend(pParse, pNew, pExpr);
- sColname.z = zColname;
- sColname.n = sqlite3Strlen30(zColname);
- sqlite3ExprListSetName(pParse, pNew, &sColname, 0);
- if( pNew && (p->selFlags & SF_NestedFrom)!=0 ){
- struct ExprList_item *pX = &pNew->a[pNew->nExpr-1];
- if( pSub ){
- pX->zSpan = sqlite3DbStrDup(db, pSub->pEList->a[j].zSpan);
- testcase( pX->zSpan==0 );
- }else{
- pX->zSpan = sqlite3MPrintf(db, "%s.%s.%s",
- zSchemaName, zTabName, zColname);
- testcase( pX->zSpan==0 );
- }
- pX->bSpanIsTab = 1;
- }
- sqlite3DbFree(db, zToFree);
- }
- }
- if( !tableSeen ){
- if( zTName ){
- sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
- }else{
- sqlite3ErrorMsg(pParse, "no tables specified");
- }
- }
- }
- }
- sqlite3ExprListDelete(db, pEList);
- p->pEList = pNew;
- }
- #if SQLITE_MAX_COLUMN
- if( p->pEList && p->pEList->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){
- sqlite3ErrorMsg(pParse, "too many columns in result set");
- }
- #endif
- return WRC_Continue;
- }
- /*
- ** No-op routine for the parse-tree walker.
- **
- ** When this routine is the Walker.xExprCallback then expression trees
- ** are walked without any actions being taken at each node. Presumably,
- ** when this routine is used for Walker.xExprCallback then
- ** Walker.xSelectCallback is set to do something useful for every
- ** subquery in the parser tree.
- */
- static int exprWalkNoop(Walker *NotUsed, Expr *NotUsed2){
- UNUSED_PARAMETER2(NotUsed, NotUsed2);
- return WRC_Continue;
- }
- /*
- ** This routine "expands" a SELECT statement and all of its subqueries.
- ** For additional information on what it means to "expand" a SELECT
- ** statement, see the comment on the selectExpand worker callback above.
- **
- ** Expanding a SELECT statement is the first step in processing a
- ** SELECT statement. The SELECT statement must be expanded before
- ** name resolution is performed.
- **
- ** If anything goes wrong, an error message is written into pParse.
- ** The calling function can detect the problem by looking at pParse->nErr
- ** and/or pParse->db->mallocFailed.
- */
- static void sqlite3SelectExpand(Parse *pParse, Select *pSelect){
- Walker w;
- memset(&w, 0, sizeof(w));
- w.xExprCallback = exprWalkNoop;
- w.pParse = pParse;
- if( pParse->hasCompound ){
- w.xSelectCallback = convertCompoundSelectToSubquery;
- sqlite3WalkSelect(&w, pSelect);
- }
- w.xSelectCallback = selectExpander;
- sqlite3WalkSelect(&w, pSelect);
- }
- #ifndef SQLITE_OMIT_SUBQUERY
- /*
- ** This is a Walker.xSelectCallback callback for the sqlite3SelectTypeInfo()
- ** interface.
- **
- ** For each FROM-clause subquery, add Column.zType and Column.zColl
- ** information to the Table structure that represents the result set
- ** of that subquery.
- **
- ** The Table structure that represents the result set was constructed
- ** by selectExpander() but the type and collation information was omitted
- ** at that point because identifiers had not yet been resolved. This
- ** routine is called after identifier resolution.
- */
- static int selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
- Parse *pParse;
- int i;
- SrcList *pTabList;
- struct SrcList_item *pFrom;
- assert( p->selFlags & SF_Resolved );
- if( (p->selFlags & SF_HasTypeInfo)==0 ){
- p->selFlags |= SF_HasTypeInfo;
- pParse = pWalker->pParse;
- pTabList = p->pSrc;
- for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
- Table *pTab = pFrom->pTab;
- if( ALWAYS(pTab!=0) && (pTab->tabFlags & TF_Ephemeral)!=0 ){
- /* A sub-query in the FROM clause of a SELECT */
- Select *pSel = pFrom->pSelect;
- assert( pSel );
- while( pSel->pPrior ) pSel = pSel->pPrior;
- selectAddColumnTypeAndCollation(pParse, pTab, pSel);
- }
- }
- }
- return WRC_Continue;
- }
- #endif
- /*
- ** This routine adds datatype and collating sequence information to
- ** the Table structures of all FROM-clause subqueries in a
- ** SELECT statement.
- **
- ** Use this routine after name resolution.
- */
- static void sqlite3SelectAddTypeInfo(Parse *pParse, Select *pSelect){
- #ifndef SQLITE_OMIT_SUBQUERY
- Walker w;
- memset(&w, 0, sizeof(w));
- w.xSelectCallback = selectAddSubqueryTypeInfo;
- w.xExprCallback = exprWalkNoop;
- w.pParse = pParse;
- w.bSelectDepthFirst = 1;
- sqlite3WalkSelect(&w, pSelect);
- #endif
- }
- /*
- ** This routine sets up a SELECT statement for processing. The
- ** following is accomplished:
- **
- ** * VDBE Cursor numbers are assigned to all FROM-clause terms.
- ** * Ephemeral Table objects are created for all FROM-clause subqueries.
- ** * ON and USING clauses are shifted into WHERE statements
- ** * Wildcards "*" and "TABLE.*" in result sets are expanded.
- ** * Identifiers in expression are matched to tables.
- **
- ** This routine acts recursively on all subqueries within the SELECT.
- */
- void sqlite3SelectPrep(
- Parse *pParse, /* The parser context */
- Select *p, /* The SELECT statement being coded. */
- NameContext *pOuterNC /* Name context for container */
- ){
- sqlite3 *db;
- if( NEVER(p==0) ) return;
- db = pParse->db;
- if( db->mallocFailed ) return;
- if( p->selFlags & SF_HasTypeInfo ) return;
- sqlite3SelectExpand(pParse, p);
- if( pParse->nErr || db->mallocFailed ) return;
- sqlite3ResolveSelectNames(pParse, p, pOuterNC);
- if( pParse->nErr || db->mallocFailed ) return;
- sqlite3SelectAddTypeInfo(pParse, p);
- }
- /*
- ** Reset the aggregate accumulator.
- **
- ** The aggregate accumulator is a set of memory cells that hold
- ** intermediate results while calculating an aggregate. This
- ** routine generates code that stores NULLs in all of those memory
- ** cells.
- */
- static void resetAccumulator(Parse *pParse, AggInfo *pAggInfo){
- Vdbe *v = pParse->pVdbe;
- int i;
- struct AggInfo_func *pFunc;
- if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
- return;
- }
- for(i=0; i<pAggInfo->nColumn; i++){
- sqlite3VdbeAddOp2(v, OP_Null, 0, pAggInfo->aCol[i].iMem);
- }
- for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
- sqlite3VdbeAddOp2(v, OP_Null, 0, pFunc->iMem);
- if( pFunc->iDistinct>=0 ){
- Expr *pE = pFunc->pExpr;
- assert( !ExprHasProperty(pE, EP_xIsSelect) );
- if( pE->x.pList==0 || pE->x.pList->nExpr!=1 ){
- sqlite3ErrorMsg(pParse, "DISTINCT aggregates must have exactly one "
- "argument");
- pFunc->iDistinct = -1;
- }else{
- KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->x.pList);
- sqlite3VdbeAddOp4(v, OP_OpenEphemeral, pFunc->iDistinct, 0, 0,
- (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
- }
- }
- }
- }
- /*
- ** Invoke the OP_AggFinalize opcode for every aggregate function
- ** in the AggInfo structure.
- */
- static void finalizeAggFunctions(Parse *pParse, AggInfo *pAggInfo){
- Vdbe *v = pParse->pVdbe;
- int i;
- struct AggInfo_func *pF;
- for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
- ExprList *pList = pF->pExpr->x.pList;
- assert( !ExprHasProperty(pF->pExpr, EP_xIsSelect) );
- sqlite3VdbeAddOp4(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0, 0,
- (void*)pF->pFunc, P4_FUNCDEF);
- }
- }
- /*
- ** Update the accumulator memory cells for an aggregate based on
- ** the current cursor position.
- */
- static void updateAccumulator(Parse *pParse, AggInfo *pAggInfo){
- Vdbe *v = pParse->pVdbe;
- int i;
- int regHit = 0;
- int addrHitTest = 0;
- struct AggInfo_func *pF;
- struct AggInfo_col *pC;
- pAggInfo->directMode = 1;
- sqlite3ExprCacheClear(pParse);
- for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
- int nArg;
- int addrNext = 0;
- int regAgg;
- ExprList *pList = pF->pExpr->x.pList;
- assert( !ExprHasProperty(pF->pExpr, EP_xIsSelect) );
- if( pList ){
- nArg = pList->nExpr;
- regAgg = sqlite3GetTempRange(pParse, nArg);
- sqlite3ExprCodeExprList(pParse, pList, regAgg, 1);
- }else{
- nArg = 0;
- regAgg = 0;
- }
- if( pF->iDistinct>=0 ){
- addrNext = sqlite3VdbeMakeLabel(v);
- assert( nArg==1 );
- codeDistinct(pParse, pF->iDistinct, addrNext, 1, regAgg);
- }
- if( pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL ){
- CollSeq *pColl = 0;
- struct ExprList_item *pItem;
- int j;
- assert( pList!=0 ); /* pList!=0 if pF->pFunc has NEEDCOLL */
- for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
- pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
- }
- if( !pColl ){
- pColl = pParse->db->pDfltColl;
- }
- if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem;
- sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0, (char *)pColl, P4_COLLSEQ);
- }
- sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
- (void*)pF->pFunc, P4_FUNCDEF);
- sqlite3VdbeChangeP5(v, (u8)nArg);
- sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
- sqlite3ReleaseTempRange(pParse, regAgg, nArg);
- if( addrNext ){
- sqlite3VdbeResolveLabel(v, addrNext);
- sqlite3ExprCacheClear(pParse);
- }
- }
- /* Before populating the accumulator registers, clear the column cache.
- ** Otherwise, if any of the required column values are already present
- ** in registers, sqlite3ExprCode() may use OP_SCopy to copy the value
- ** to pC->iMem. But by the time the value is used, the original register
- ** may have been used, invalidating the underlying buffer holding the
- ** text or blob value. See ticket [883034dcb5].
- **
- ** Another solution would be to change the OP_SCopy used to copy cached
- ** values to an OP_Copy.
- */
- if( regHit ){
- addrHitTest = sqlite3VdbeAddOp1(v, OP_If, regHit);
- }
- sqlite3ExprCacheClear(pParse);
- for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
- sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
- }
- pAggInfo->directMode = 0;
- sqlite3ExprCacheClear(pParse);
- if( addrHitTest ){
- sqlite3VdbeJumpHere(v, addrHitTest);
- }
- }
- /*
- ** Add a single OP_Explain instruction to the VDBE to explain a simple
- ** count(*) query ("SELECT count(*) FROM pTab").
- */
- #ifndef SQLITE_OMIT_EXPLAIN
- static void explainSimpleCount(
- Parse *pParse, /* Parse context */
- Table *pTab, /* Table being queried */
- Index *pIdx /* Index used to optimize scan, or NULL */
- ){
- if( pParse->explain==2 ){
- char *zEqp = sqlite3MPrintf(pParse->db, "SCAN TABLE %s%s%s",
- pTab->zName,
- pIdx ? " USING COVERING INDEX " : "",
- pIdx ? pIdx->zName : ""
- );
- sqlite3VdbeAddOp4(
- pParse->pVdbe, OP_Explain, pParse->iSelectId, 0, 0, zEqp, P4_DYNAMIC
- );
- }
- }
- #else
- # define explainSimpleCount(a,b,c)
- #endif
- /*
- ** Generate code for the SELECT statement given in the p argument.
- **
- ** The results are distributed in various ways depending on the
- ** contents of the SelectDest structure pointed to by argument pDest
- ** as follows:
- **
- ** pDest->eDest Result
- ** ------------ -------------------------------------------
- ** SRT_Output Generate a row of output (using the OP_ResultRow
- ** opcode) for each row in the result set.
- **
- ** SRT_Mem Only valid if the result is a single column.
- ** Store the first column of the first result row
- ** in register pDest->iSDParm then abandon the rest
- ** of the query. This destination implies "LIMIT 1".
- **
- ** SRT_Set The result must be a single column. Store each
- ** row of result as the key in table pDest->iSDParm.
- ** Apply the affinity pDest->affSdst before storing
- ** results. Used to implement "IN (SELECT ...)".
- **
- ** SRT_Union Store results as a key in a temporary table
- ** identified by pDest->iSDParm.
- **
- ** SRT_Except Remove results from the temporary table pDest->iSDParm.
- **
- ** SRT_Table Store results in temporary table pDest->iSDParm.
- ** This is like SRT_EphemTab except that the table
- ** is assumed to already be open.
- **
- ** SRT_EphemTab Create an temporary table pDest->iSDParm and store
- ** the result there. The cursor is left open after
- ** returning. This is like SRT_Table except that
- ** this destination uses OP_OpenEphemeral to create
- ** the table first.
- **
- ** SRT_Coroutine Generate a co-routine that returns a new row of
- ** results each time it is invoked. The entry point
- ** of the co-routine is stored in register pDest->iSDParm.
- **
- ** SRT_Exists Store a 1 in memory cell pDest->iSDParm if the result
- ** set is not empty.
- **
- ** SRT_Discard Throw the results away. This is used by SELECT
- ** statements within triggers whose only purpose is
- ** the side-effects of functions.
- **
- ** This routine returns the number of errors. If any errors are
- ** encountered, then an appropriate error message is left in
- ** pParse->zErrMsg.
- **
- ** This routine does NOT free the Select structure passed in. The
- ** calling function needs to do that.
- */
- int sqlite3Select(
- Parse *pParse, /* The parser context */
- Select *p, /* The SELECT statement being coded. */
- SelectDest *pDest /* What to do with the query results */
- ){
- int i, j; /* Loop counters */
- WhereInfo *pWInfo; /* Return from sqlite3WhereBegin() */
- Vdbe *v; /* The virtual machine under construction */
- int isAgg; /* True for select lists like "count(*)" */
- ExprList *pEList; /* List of columns to extract. */
- SrcList *pTabList; /* List of tables to select from */
- Expr *pWhere; /* The WHERE clause. May be NULL */
- ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
- ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */
- Expr *pHaving; /* The HAVING clause. May be NULL */
- int rc = 1; /* Value to return from this function */
- int addrSortIndex; /* Address of an OP_OpenEphemeral instruction */
- DistinctCtx sDistinct; /* Info on how to code the DISTINCT keyword */
- AggInfo sAggInfo; /* Information used by aggregate queries */
- int iEnd; /* Address of the end of the query */
- sqlite3 *db; /* The database connection */
- #ifndef SQLITE_OMIT_EXPLAIN
- int iRestoreSelectId = pParse->iSelectId;
- pParse->iSelectId = pParse->iNextSelectId++;
- #endif
- db = pParse->db;
- if( p==0 || db->mallocFailed || pParse->nErr ){
- return 1;
- }
- if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
- memset(&sAggInfo, 0, sizeof(sAggInfo));
- if( IgnorableOrderby(pDest) ){
- assert(pDest->eDest==SRT_Exists || pDest->eDest==SRT_Union ||
- pDest->eDest==SRT_Except || pDest->eDest==SRT_Discard);
- /* If ORDER BY makes no difference in the output then neither does
- ** DISTINCT so it can be removed too. */
- sqlite3ExprListDelete(db, p->pOrderBy);
- p->pOrderBy = 0;
- p->selFlags &= ~SF_Distinct;
- }
- sqlite3SelectPrep(pParse, p, 0);
- pOrderBy = p->pOrderBy;
- pTabList = p->pSrc;
- pEList = p->pEList;
- if( pParse->nErr || db->mallocFailed ){
- goto select_end;
- }
- isAgg = (p->selFlags & SF_Aggregate)!=0;
- assert( pEList!=0 );
- /* Begin generating code.
- */
- v = sqlite3GetVdbe(pParse);
- if( v==0 ) goto select_end;
- /* If writing to memory or generating a set
- ** only a single column may be output.
- */
- #ifndef SQLITE_OMIT_SUBQUERY
- if( checkForMultiColumnSelectError(pParse, pDest, pEList->nExpr) ){
- goto select_end;
- }
- #endif
- /* Generate code for all sub-queries in the FROM clause
- */
- #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
- for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
- struct SrcList_item *pItem = &pTabList->a[i];
- SelectDest dest;
- Select *pSub = pItem->pSelect;
- int isAggSub;
- if( pSub==0 ) continue;
- /* Sometimes the code for a subquery will be generated more than
- ** once, if the subquery is part of the WHERE clause in a LEFT JOIN,
- ** for example. In that case, do not regenerate the code to manifest
- ** a view or the co-routine to implement a view. The first instance
- ** is sufficient, though the subroutine to manifest the view does need
- ** to be invoked again. */
- if( pItem->addrFillSub ){
- if( pItem->viaCoroutine==0 ){
- sqlite3VdbeAddOp2(v, OP_Gosub, pItem->regReturn, pItem->addrFillSub);
- }
- continue;
- }
- /* Increment Parse.nHeight by the height of the largest expression
- ** tree referred to by this, the parent select. The child select
- ** may contain expression trees of at most
- ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
- ** more conservative than necessary, but much easier than enforcing
- ** an exact limit.
- */
- pParse->nHeight += sqlite3SelectExprHeight(p);
- isAggSub = (pSub->selFlags & SF_Aggregate)!=0;
- if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
- /* This subquery can be absorbed into its parent. */
- if( isAggSub ){
- isAgg = 1;
- p->selFlags |= SF_Aggregate;
- }
- i = -1;
- }else if( pTabList->nSrc==1 && (p->selFlags & SF_Materialize)==0
- && OptimizationEnabled(db, SQLITE_SubqCoroutine)
- ){
- /* Implement a co-routine that will return a single row of the result
- ** set on each invocation.
- */
- int addrTop;
- int addrEof;
- pItem->regReturn = ++pParse->nMem;
- addrEof = ++pParse->nMem;
- /* Before coding the OP_Goto to jump to the start of the main routine,
- ** ensure that the jump to the verify-schema routine has already
- ** been coded. Otherwise, the verify-schema would likely be coded as
- ** part of the co-routine. If the main routine then accessed the
- ** database before invoking the co-routine for the first time (for
- ** example to initialize a LIMIT register from a sub-select), it would
- ** be doing so without having verified the schema version and obtained
- ** the required db locks. See ticket d6b36be38. */
- sqlite3CodeVerifySchema(pParse, -1);
- sqlite3VdbeAddOp0(v, OP_Goto);
- addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
- sqlite3VdbeChangeP5(v, 1);
- VdbeComment((v, "coroutine for %s", pItem->pTab->zName));
- pItem->addrFillSub = addrTop;
- sqlite3VdbeAddOp2(v, OP_Integer, 0, addrEof);
- sqlite3VdbeChangeP5(v, 1);
- sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
- explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
- sqlite3Select(pParse, pSub, &dest);
- pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
- pItem->viaCoroutine = 1;
- sqlite3VdbeChangeP2(v, addrTop, dest.iSdst);
- sqlite3VdbeChangeP3(v, addrTop, dest.nSdst);
- sqlite3VdbeAddOp2(v, OP_Integer, 1, addrEof);
- sqlite3VdbeAddOp1(v, OP_Yield, pItem->regReturn);
- VdbeComment((v, "end %s", pItem->pTab->zName));
- sqlite3VdbeJumpHere(v, addrTop-1);
- sqlite3ClearTempRegCache(pParse);
- }else{
- /* Generate a subroutine that will fill an ephemeral table with
- ** the content of this subquery. pItem->addrFillSub will point
- ** to the address of the generated subroutine. pItem->regReturn
- ** is a register allocated to hold the subroutine return address
- */
- int topAddr;
- int onceAddr = 0;
- int retAddr;
- assert( pItem->addrFillSub==0 );
- pItem->regReturn = ++pParse->nMem;
- topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
- pItem->addrFillSub = topAddr+1;
- VdbeNoopComment((v, "materialize %s", pItem->pTab->zName));
- if( pItem->isCorrelated==0 ){
- /* If the subquery is not correlated and if we are not inside of
- ** a trigger, then we only need to compute the value of the subquery
- ** once. */
- onceAddr = sqlite3CodeOnce(pParse);
- }
- sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
- explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
- sqlite3Select(pParse, pSub, &dest);
- pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
- if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
- retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
- VdbeComment((v, "end %s", pItem->pTab->zName));
- sqlite3VdbeChangeP1(v, topAddr, retAddr);
- sqlite3ClearTempRegCache(pParse);
- }
- if( /*pParse->nErr ||*/ db->mallocFailed ){
- goto select_end;
- }
- pParse->nHeight -= sqlite3SelectExprHeight(p);
- pTabList = p->pSrc;
- if( !IgnorableOrderby(pDest) ){
- pOrderBy = p->pOrderBy;
- }
- }
- pEList = p->pEList;
- #endif
- pWhere = p->pWhere;
- pGroupBy = p->pGroupBy;
- pHaving = p->pHaving;
- sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0;
- #ifndef SQLITE_OMIT_COMPOUND_SELECT
- /* If there is are a sequence of queries, do the earlier ones first.
- */
- if( p->pPrior ){
- if( p->pRightmost==0 ){
- Select *pLoop, *pRight = 0;
- int cnt = 0;
- int mxSelect;
- for(pLoop=p; pLoop; pLoop=pLoop->pPrior, cnt++){
- pLoop->pRightmost = p;
- pLoop->pNext = pRight;
- pRight = pLoop;
- }
- mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
- if( mxSelect && cnt>mxSelect ){
- sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
- goto select_end;
- }
- }
- rc = multiSelect(pParse, p, pDest);
- explainSetInteger(pParse->iSelectId, iRestoreSelectId);
- return rc;
- }
- #endif
- /* If there is both a GROUP BY and an ORDER BY clause and they are
- ** identical, then disable the ORDER BY clause since the GROUP BY
- ** will cause elements to come out in the correct order. This is
- ** an optimization - the correct answer should result regardless.
- ** Use the SQLITE_GroupByOrder flag with SQLITE_TESTCTRL_OPTIMIZER
- ** to disable this optimization for testing purposes.
- */
- if( sqlite3ExprListCompare(p->pGroupBy, pOrderBy, -1)==0
- && OptimizationEnabled(db, SQLITE_GroupByOrder) ){
- pOrderBy = 0;
- }
- /* If the query is DISTINCT with an ORDER BY but is not an aggregate, and
- ** if the select-list is the same as the ORDER BY list, then this query
- ** can be rewritten as a GROUP BY. In other words, this:
- **
- ** SELECT DISTINCT xyz FROM ... ORDER BY xyz
- **
- ** is transformed to:
- **
- ** SELECT xyz FROM ... GROUP BY xyz
- **
- ** The second form is preferred as a single index (or temp-table) may be
- ** used for both the ORDER BY and DISTINCT processing. As originally
- ** written the query must use a temp-table for at least one of the ORDER
- ** BY and DISTINCT, and an index or separate temp-table for the other.
- */
- if( (p->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct
- && sqlite3ExprListCompare(pOrderBy, p->pEList, -1)==0
- ){
- p->selFlags &= ~SF_Distinct;
- p->pGroupBy = sqlite3ExprListDup(db, p->pEList, 0);
- pGroupBy = p->pGroupBy;
- pOrderBy = 0;
- /* Notice that even thought SF_Distinct has been cleared from p->selFlags,
- ** the sDistinct.isTnct is still set. Hence, isTnct represents the
- ** original setting of the SF_Distinct flag, not the current setting */
- assert( sDistinct.isTnct );
- }
- /* If there is an ORDER BY clause, then this sorting
- ** index might end up being unused if the data can be
- ** extracted in pre-sorted order. If that is the case, then the
- ** OP_OpenEphemeral instruction will be changed to an OP_Noop once
- ** we figure out that the sorting index is not needed. The addrSortIndex
- ** variable is used to facilitate that change.
- */
- if( pOrderBy ){
- KeyInfo *pKeyInfo;
- pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
- pOrderBy->iECursor = pParse->nTab++;
- p->addrOpenEphm[2] = addrSortIndex =
- sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
- pOrderBy->iECursor, pOrderBy->nExpr+2, 0,
- (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
- }else{
- addrSortIndex = -1;
- }
- /* If the output is destined for a temporary table, open that table.
- */
- if( pDest->eDest==SRT_EphemTab ){
- sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pDest->iSDParm, pEList->nExpr);
- }
- /* Set the limiter.
- */
- iEnd = sqlite3VdbeMakeLabel(v);
- p->nSelectRow = LARGEST_INT64;
- computeLimitRegisters(pParse, p, iEnd);
- if( p->iLimit==0 && addrSortIndex>=0 ){
- sqlite3VdbeGetOp(v, addrSortIndex)->opcode = OP_SorterOpen;
- p->selFlags |= SF_UseSorter;
- }
- /* Open a virtual index to use for the distinct set.
- */
- if( p->selFlags & SF_Distinct ){
- sDistinct.tabTnct = pParse->nTab++;
- sDistinct.addrTnct = sqlite3VdbeAddOp4(v, OP_OpenEphemeral,
- sDistinct.tabTnct, 0, 0,
- (char*)keyInfoFromExprList(pParse, p->pEList),
- P4_KEYINFO_HANDOFF);
- sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
- sDistinct.eTnctType = WHERE_DISTINCT_UNORDERED;
- }else{
- sDistinct.eTnctType = WHERE_DISTINCT_NOOP;
- }
- if( !isAgg && pGroupBy==0 ){
- /* No aggregate functions and no GROUP BY clause */
- u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0);
- /* Begin the database scan. */
- pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pOrderBy, p->pEList,
- wctrlFlags, 0);
- if( pWInfo==0 ) goto select_end;
- if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){
- p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo);
- }
- if( sDistinct.isTnct && sqlite3WhereIsDistinct(pWInfo) ){
- sDistinct.eTnctType = sqlite3WhereIsDistinct(pWInfo);
- }
- if( pOrderBy && sqlite3WhereIsOrdered(pWInfo) ) pOrderBy = 0;
- /* If sorting index that was created by a prior OP_OpenEphemeral
- ** instruction ended up not being needed, then change the OP_OpenEphemeral
- ** into an OP_Noop.
- */
- if( addrSortIndex>=0 && pOrderBy==0 ){
- sqlite3VdbeChangeToNoop(v, addrSortIndex);
- p->addrOpenEphm[2] = -1;
- }
- /* Use the standard inner loop. */
- selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, &sDistinct, pDest,
- sqlite3WhereContinueLabel(pWInfo),
- sqlite3WhereBreakLabel(pWInfo));
- /* End the database scan loop.
- */
- sqlite3WhereEnd(pWInfo);
- }else{
- /* This case when there exist aggregate functions or a GROUP BY clause
- ** or both */
- NameContext sNC; /* Name context for processing aggregate information */
- int iAMem; /* First Mem address for storing current GROUP BY */
- int iBMem; /* First Mem address for previous GROUP BY */
- int iUseFlag; /* Mem address holding flag indicating that at least
- ** one row of the input to the aggregator has been
- ** processed */
- int iAbortFlag; /* Mem address which causes query abort if positive */
- int groupBySort; /* Rows come from source in GROUP BY order */
- int addrEnd; /* End of processing for this SELECT */
- int sortPTab = 0; /* Pseudotable used to decode sorting results */
- int sortOut = 0; /* Output register from the sorter */
- /* Remove any and all aliases between the result set and the
- ** GROUP BY clause.
- */
- if( pGroupBy ){
- int k; /* Loop counter */
- struct ExprList_item *pItem; /* For looping over expression in a list */
- for(k=p->pEList->nExpr, pItem=p->pEList->a; k>0; k--, pItem++){
- pItem->iAlias = 0;
- }
- for(k=pGroupBy->nExpr, pItem=pGroupBy->a; k>0; k--, pItem++){
- pItem->iAlias = 0;
- }
- if( p->nSelectRow>100 ) p->nSelectRow = 100;
- }else{
- p->nSelectRow = 1;
- }
-
- /* Create a label to jump to when we want to abort the query */
- addrEnd = sqlite3VdbeMakeLabel(v);
- /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
- ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
- ** SELECT statement.
- */
- memset(&sNC, 0, sizeof(sNC));
- sNC.pParse = pParse;
- sNC.pSrcList = pTabList;
- sNC.pAggInfo = &sAggInfo;
- sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
- sAggInfo.pGroupBy = pGroupBy;
- sqlite3ExprAnalyzeAggList(&sNC, pEList);
- sqlite3ExprAnalyzeAggList(&sNC, pOrderBy);
- if( pHaving ){
- sqlite3ExprAnalyzeAggregates(&sNC, pHaving);
- }
- sAggInfo.nAccumulator = sAggInfo.nColumn;
- for(i=0; i<sAggInfo.nFunc; i++){
- assert( !ExprHasProperty(sAggInfo.aFunc[i].pExpr, EP_xIsSelect) );
- sNC.ncFlags |= NC_InAggFunc;
- sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->x.pList);
- sNC.ncFlags &= ~NC_InAggFunc;
- }
- if( db->mallocFailed ) goto select_end;
- /* Processing for aggregates with GROUP BY is very different and
- ** much more complex than aggregates without a GROUP BY.
- */
- if( pGroupBy ){
- KeyInfo *pKeyInfo; /* Keying information for the group by clause */
- int j1; /* A-vs-B comparision jump */
- int addrOutputRow; /* Start of subroutine that outputs a result row */
- int regOutputRow; /* Return address register for output subroutine */
- int addrSetAbort; /* Set the abort flag and return */
- int addrTopOfLoop; /* Top of the input loop */
- int addrSortingIdx; /* The OP_OpenEphemeral for the sorting index */
- int addrReset; /* Subroutine for resetting the accumulator */
- int regReset; /* Return address register for reset subroutine */
- /* If there is a GROUP BY clause we might need a sorting index to
- ** implement it. Allocate that sorting index now. If it turns out
- ** that we do not need it after all, the OP_SorterOpen instruction
- ** will be converted into a Noop.
- */
- sAggInfo.sortingIdx = pParse->nTab++;
- pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
- addrSortingIdx = sqlite3VdbeAddOp4(v, OP_SorterOpen,
- sAggInfo.sortingIdx, sAggInfo.nSortingColumn,
- 0, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
- /* Initialize memory locations used by GROUP BY aggregate processing
- */
- iUseFlag = ++pParse->nMem;
- iAbortFlag = ++pParse->nMem;
- regOutputRow = ++pParse->nMem;
- addrOutputRow = sqlite3VdbeMakeLabel(v);
- regReset = ++pParse->nMem;
- addrReset = sqlite3VdbeMakeLabel(v);
- iAMem = pParse->nMem + 1;
- pParse->nMem += pGroupBy->nExpr;
- iBMem = pParse->nMem + 1;
- pParse->nMem += pGroupBy->nExpr;
- sqlite3VdbeAddOp2(v, OP_Integer, 0, iAbortFlag);
- VdbeComment((v, "clear abort flag"));
- sqlite3VdbeAddOp2(v, OP_Integer, 0, iUseFlag);
- VdbeComment((v, "indicate accumulator empty"));
- sqlite3VdbeAddOp3(v, OP_Null, 0, iAMem, iAMem+pGroupBy->nExpr-1);
- /* Begin a loop that will extract all source rows in GROUP BY order.
- ** This might involve two separate loops with an OP_Sort in between, or
- ** it might be a single loop that uses an index to extract information
- ** in the right order to begin with.
- */
- sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
- pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, 0,
- WHERE_GROUPBY, 0);
- if( pWInfo==0 ) goto select_end;
- if( sqlite3WhereIsOrdered(pWInfo) ){
- /* The optimizer is able to deliver rows in group by order so
- ** we do not have to sort. The OP_OpenEphemeral table will be
- ** cancelled later because we still need to use the pKeyInfo
- */
- groupBySort = 0;
- }else{
- /* Rows are coming out in undetermined order. We have to push
- ** each row into a sorting index, terminate the first loop,
- ** then loop over the sorting index in order to get the output
- ** in sorted order
- */
- int regBase;
- int regRecord;
- int nCol;
- int nGroupBy;
- explainTempTable(pParse,
- (sDistinct.isTnct && (p->selFlags&SF_Distinct)==0) ?
- "DISTINCT" : "GROUP BY");
- groupBySort = 1;
- nGroupBy = pGroupBy->nExpr;
- nCol = nGroupBy + 1;
- j = nGroupBy+1;
- for(i=0; i<sAggInfo.nColumn; i++){
- if( sAggInfo.aCol[i].iSorterColumn>=j ){
- nCol++;
- j++;
- }
- }
- regBase = sqlite3GetTempRange(pParse, nCol);
- sqlite3ExprCacheClear(pParse);
- sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0);
- sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx,regBase+nGroupBy);
- j = nGroupBy+1;
- for(i=0; i<sAggInfo.nColumn; i++){
- struct AggInfo_col *pCol = &sAggInfo.aCol[i];
- if( pCol->iSorterColumn>=j ){
- int r1 = j + regBase;
- int r2;
- r2 = sqlite3ExprCodeGetColumn(pParse,
- pCol->pTab, pCol->iColumn, pCol->iTable, r1, 0);
- if( r1!=r2 ){
- sqlite3VdbeAddOp2(v, OP_SCopy, r2, r1);
- }
- j++;
- }
- }
- regRecord = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regRecord);
- sqlite3VdbeAddOp2(v, OP_SorterInsert, sAggInfo.sortingIdx, regRecord);
- sqlite3ReleaseTempReg(pParse, regRecord);
- sqlite3ReleaseTempRange(pParse, regBase, nCol);
- sqlite3WhereEnd(pWInfo);
- sAggInfo.sortingIdxPTab = sortPTab = pParse->nTab++;
- sortOut = sqlite3GetTempReg(pParse);
- sqlite3VdbeAddOp3(v, OP_OpenPseudo, sortPTab, sortOut, nCol);
- sqlite3VdbeAddOp2(v, OP_SorterSort, sAggInfo.sortingIdx, addrEnd);
- VdbeComment((v, "GROUP BY sort"));
- sAggInfo.useSortingIdx = 1;
- sqlite3ExprCacheClear(pParse);
- }
- /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
- ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
- ** Then compare the current GROUP BY terms against the GROUP BY terms
- ** from the previous row currently stored in a0, a1, a2...
- */
- addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
- sqlite3ExprCacheClear(pParse);
- if( groupBySort ){
- sqlite3VdbeAddOp2(v, OP_SorterData, sAggInfo.sortingIdx, sortOut);
- }
- for(j=0; j<pGroupBy->nExpr; j++){
- if( groupBySort ){
- sqlite3VdbeAddOp3(v, OP_Column, sortPTab, j, iBMem+j);
- if( j==0 ) sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
- }else{
- sAggInfo.directMode = 1;
- sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, iBMem+j);
- }
- }
- sqlite3VdbeAddOp4(v, OP_Compare, iAMem, iBMem, pGroupBy->nExpr,
- (char*)pKeyInfo, P4_KEYINFO);
- j1 = sqlite3VdbeCurrentAddr(v);
- sqlite3VdbeAddOp3(v, OP_Jump, j1+1, 0, j1+1);
- /* Generate code that runs whenever the GROUP BY changes.
- ** Changes in the GROUP BY are detected by the previous code
- ** block. If there were no changes, this block is skipped.
- **
- ** This code copies current group by terms in b0,b1,b2,...
- ** over to a0,a1,a2. It then calls the output subroutine
- ** and resets the aggregate accumulator registers in preparation
- ** for the next GROUP BY batch.
- */
- sqlite3ExprCodeMove(pParse, iBMem, iAMem, pGroupBy->nExpr);
- sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
- VdbeComment((v, "output one row"));
- sqlite3VdbeAddOp2(v, OP_IfPos, iAbortFlag, addrEnd);
- VdbeComment((v, "check abort flag"));
- sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
- VdbeComment((v, "reset accumulator"));
- /* Update the aggregate accumulators based on the content of
- ** the current row
- */
- sqlite3VdbeJumpHere(v, j1);
- updateAccumulator(pParse, &sAggInfo);
- sqlite3VdbeAddOp2(v, OP_Integer, 1, iUseFlag);
- VdbeComment((v, "indicate data in accumulator"));
- /* End of the loop
- */
- if( groupBySort ){
- sqlite3VdbeAddOp2(v, OP_SorterNext, sAggInfo.sortingIdx, addrTopOfLoop);
- }else{
- sqlite3WhereEnd(pWInfo);
- sqlite3VdbeChangeToNoop(v, addrSortingIdx);
- }
- /* Output the final row of result
- */
- sqlite3VdbeAddOp2(v, OP_Gosub, regOutputRow, addrOutputRow);
- VdbeComment((v, "output final row"));
- /* Jump over the subroutines
- */
- sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEnd);
- /* Generate a subroutine that outputs a single row of the result
- ** set. This subroutine first looks at the iUseFlag. If iUseFlag
- ** is less than or equal to zero, the subroutine is a no-op. If
- ** the processing calls for the query to abort, this subroutine
- ** increments the iAbortFlag memory location before returning in
- ** order to signal the caller to abort.
- */
- addrSetAbort = sqlite3VdbeCurrentAddr(v);
- sqlite3VdbeAddOp2(v, OP_Integer, 1, iAbortFlag);
- VdbeComment((v, "set abort flag"));
- sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
- sqlite3VdbeResolveLabel(v, addrOutputRow);
- addrOutputRow = sqlite3VdbeCurrentAddr(v);
- sqlite3VdbeAddOp2(v, OP_IfPos, iUseFlag, addrOutputRow+2);
- VdbeComment((v, "Groupby result generator entry point"));
- sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
- finalizeAggFunctions(pParse, &sAggInfo);
- sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
- selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
- &sDistinct, pDest,
- addrOutputRow+1, addrSetAbort);
- sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
- VdbeComment((v, "end groupby result generator"));
- /* Generate a subroutine that will reset the group-by accumulator
- */
- sqlite3VdbeResolveLabel(v, addrReset);
- resetAccumulator(pParse, &sAggInfo);
- sqlite3VdbeAddOp1(v, OP_Return, regReset);
-
- } /* endif pGroupBy. Begin aggregate queries without GROUP BY: */
- else {
- ExprList *pDel = 0;
- #ifndef SQLITE_OMIT_BTREECOUNT
- Table *pTab;
- if( (pTab = isSimpleCount(p, &sAggInfo))!=0 ){
- /* If isSimpleCount() returns a pointer to a Table structure, then
- ** the SQL statement is of the form:
- **
- ** SELECT count(*) FROM <tbl>
- **
- ** where the Table structure returned represents table <tbl>.
- **
- ** This statement is so common that it is optimized specially. The
- ** OP_Count instruction is executed either on the intkey table that
- ** contains the data for table <tbl> or on one of its indexes. It
- ** is better to execute the op on an index, as indexes are almost
- ** always spread across less pages than their corresponding tables.
- */
- const int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
- const int iCsr = pParse->nTab++; /* Cursor to scan b-tree */
- Index *pIdx; /* Iterator variable */
- KeyInfo *pKeyInfo = 0; /* Keyinfo for scanned index */
- Index *pBest = 0; /* Best index found so far */
- int iRoot = pTab->tnum; /* Root page of scanned b-tree */
- sqlite3CodeVerifySchema(pParse, iDb);
- sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
- /* Search for the index that has the lowest scan cost.
- **
- ** (2011-04-15) Do not do a full scan of an unordered index.
- **
- ** (2013-10-03) Do not count the entires in a partial index.
- **
- ** In practice the KeyInfo structure will not be used. It is only
- ** passed to keep OP_OpenRead happy.
- */
- for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
- if( pIdx->bUnordered==0
- && pIdx->szIdxRow<pTab->szTabRow
- && pIdx->pPartIdxWhere==0
- && (!pBest || pIdx->szIdxRow<pBest->szIdxRow)
- ){
- pBest = pIdx;
- }
- }
- if( pBest ){
- iRoot = pBest->tnum;
- pKeyInfo = sqlite3IndexKeyinfo(pParse, pBest);
- }
- /* Open a read-only cursor, execute the OP_Count, close the cursor. */
- sqlite3VdbeAddOp3(v, OP_OpenRead, iCsr, iRoot, iDb);
- if( pKeyInfo ){
- sqlite3VdbeChangeP4(v, -1, (char *)pKeyInfo, P4_KEYINFO_HANDOFF);
- }
- sqlite3VdbeAddOp2(v, OP_Count, iCsr, sAggInfo.aFunc[0].iMem);
- sqlite3VdbeAddOp1(v, OP_Close, iCsr);
- explainSimpleCount(pParse, pTab, pBest);
- }else
- #endif /* SQLITE_OMIT_BTREECOUNT */
- {
- /* Check if the query is of one of the following forms:
- **
- ** SELECT min(x) FROM ...
- ** SELECT max(x) FROM ...
- **
- ** If it is, then ask the code in where.c to attempt to sort results
- ** as if there was an "ORDER ON x" or "ORDER ON x DESC" clause.
- ** If where.c is able to produce results sorted in this order, then
- ** add vdbe code to break out of the processing loop after the
- ** first iteration (since the first iteration of the loop is
- ** guaranteed to operate on the row with the minimum or maximum
- ** value of x, the only row required).
- **
- ** A special flag must be passed to sqlite3WhereBegin() to slightly
- ** modify behavior as follows:
- **
- ** + If the query is a "SELECT min(x)", then the loop coded by
- ** where.c should not iterate over any values with a NULL value
- ** for x.
- **
- ** + The optimizer code in where.c (the thing that decides which
- ** index or indices to use) should place a different priority on
- ** satisfying the 'ORDER BY' clause than it does in other cases.
- ** Refer to code and comments in where.c for details.
- */
- ExprList *pMinMax = 0;
- u8 flag = WHERE_ORDERBY_NORMAL;
-
- assert( p->pGroupBy==0 );
- assert( flag==0 );
- if( p->pHaving==0 ){
- flag = minMaxQuery(&sAggInfo, &pMinMax);
- }
- assert( flag==0 || (pMinMax!=0 && pMinMax->nExpr==1) );
- if( flag ){
- pMinMax = sqlite3ExprListDup(db, pMinMax, 0);
- pDel = pMinMax;
- if( pMinMax && !db->mallocFailed ){
- pMinMax->a[0].sortOrder = flag!=WHERE_ORDERBY_MIN ?1:0;
- pMinMax->a[0].pExpr->op = TK_COLUMN;
- }
- }
-
- /* This case runs if the aggregate has no GROUP BY clause. The
- ** processing is much simpler since there is only a single row
- ** of output.
- */
- resetAccumulator(pParse, &sAggInfo);
- pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMax,0,flag,0);
- if( pWInfo==0 ){
- sqlite3ExprListDelete(db, pDel);
- goto select_end;
- }
- updateAccumulator(pParse, &sAggInfo);
- assert( pMinMax==0 || pMinMax->nExpr==1 );
- if( sqlite3WhereIsOrdered(pWInfo) ){
- sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3WhereBreakLabel(pWInfo));
- VdbeComment((v, "%s() by index",
- (flag==WHERE_ORDERBY_MIN?"min":"max")));
- }
- sqlite3WhereEnd(pWInfo);
- finalizeAggFunctions(pParse, &sAggInfo);
- }
- pOrderBy = 0;
- sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
- selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, 0,
- pDest, addrEnd, addrEnd);
- sqlite3ExprListDelete(db, pDel);
- }
- sqlite3VdbeResolveLabel(v, addrEnd);
-
- } /* endif aggregate query */
- if( sDistinct.eTnctType==WHERE_DISTINCT_UNORDERED ){
- explainTempTable(pParse, "DISTINCT");
- }
- /* If there is an ORDER BY clause, then we need to sort the results
- ** and send them to the callback one by one.
- */
- if( pOrderBy ){
- explainTempTable(pParse, "ORDER BY");
- generateSortTail(pParse, p, v, pEList->nExpr, pDest);
- }
- /* Jump here to skip this query
- */
- sqlite3VdbeResolveLabel(v, iEnd);
- /* The SELECT was successfully coded. Set the return code to 0
- ** to indicate no errors.
- */
- rc = 0;
- /* Control jumps to here if an error is encountered above, or upon
- ** successful coding of the SELECT.
- */
- select_end:
- explainSetInteger(pParse->iSelectId, iRestoreSelectId);
- /* Identify column names if results of the SELECT are to be output.
- */
- if( rc==SQLITE_OK && pDest->eDest==SRT_Output ){
- generateColumnNames(pParse, pTabList, pEList);
- }
- sqlite3DbFree(db, sAggInfo.aCol);
- sqlite3DbFree(db, sAggInfo.aFunc);
- return rc;
- }
- #if defined(SQLITE_ENABLE_TREE_EXPLAIN)
- /*
- ** Generate a human-readable description of a the Select object.
- */
- static void explainOneSelect(Vdbe *pVdbe, Select *p){
- sqlite3ExplainPrintf(pVdbe, "SELECT ");
- if( p->selFlags & (SF_Distinct|SF_Aggregate) ){
- if( p->selFlags & SF_Distinct ){
- sqlite3ExplainPrintf(pVdbe, "DISTINCT ");
- }
- if( p->selFlags & SF_Aggregate ){
- sqlite3ExplainPrintf(pVdbe, "agg_flag ");
- }
- sqlite3ExplainNL(pVdbe);
- sqlite3ExplainPrintf(pVdbe, " ");
- }
- sqlite3ExplainExprList(pVdbe, p->pEList);
- sqlite3ExplainNL(pVdbe);
- if( p->pSrc && p->pSrc->nSrc ){
- int i;
- sqlite3ExplainPrintf(pVdbe, "FROM ");
- sqlite3ExplainPush(pVdbe);
- for(i=0; i<p->pSrc->nSrc; i++){
- struct SrcList_item *pItem = &p->pSrc->a[i];
- sqlite3ExplainPrintf(pVdbe, "{%d,*} = ", pItem->iCursor);
- if( pItem->pSelect ){
- sqlite3ExplainSelect(pVdbe, pItem->pSelect);
- if( pItem->pTab ){
- sqlite3ExplainPrintf(pVdbe, " (tabname=%s)", pItem->pTab->zName);
- }
- }else if( pItem->zName ){
- sqlite3ExplainPrintf(pVdbe, "%s", pItem->zName);
- }
- if( pItem->zAlias ){
- sqlite3ExplainPrintf(pVdbe, " (AS %s)", pItem->zAlias);
- }
- if( pItem->jointype & JT_LEFT ){
- sqlite3ExplainPrintf(pVdbe, " LEFT-JOIN");
- }
- sqlite3ExplainNL(pVdbe);
- }
- sqlite3ExplainPop(pVdbe);
- }
- if( p->pWhere ){
- sqlite3ExplainPrintf(pVdbe, "WHERE ");
- sqlite3ExplainExpr(pVdbe, p->pWhere);
- sqlite3ExplainNL(pVdbe);
- }
- if( p->pGroupBy ){
- sqlite3ExplainPrintf(pVdbe, "GROUPBY ");
- sqlite3ExplainExprList(pVdbe, p->pGroupBy);
- sqlite3ExplainNL(pVdbe);
- }
- if( p->pHaving ){
- sqlite3ExplainPrintf(pVdbe, "HAVING ");
- sqlite3ExplainExpr(pVdbe, p->pHaving);
- sqlite3ExplainNL(pVdbe);
- }
- if( p->pOrderBy ){
- sqlite3ExplainPrintf(pVdbe, "ORDERBY ");
- sqlite3ExplainExprList(pVdbe, p->pOrderBy);
- sqlite3ExplainNL(pVdbe);
- }
- if( p->pLimit ){
- sqlite3ExplainPrintf(pVdbe, "LIMIT ");
- sqlite3ExplainExpr(pVdbe, p->pLimit);
- sqlite3ExplainNL(pVdbe);
- }
- if( p->pOffset ){
- sqlite3ExplainPrintf(pVdbe, "OFFSET ");
- sqlite3ExplainExpr(pVdbe, p->pOffset);
- sqlite3ExplainNL(pVdbe);
- }
- }
- void sqlite3ExplainSelect(Vdbe *pVdbe, Select *p){
- if( p==0 ){
- sqlite3ExplainPrintf(pVdbe, "(null-select)");
- return;
- }
- while( p->pPrior ){
- p->pPrior->pNext = p;
- p = p->pPrior;
- }
- sqlite3ExplainPush(pVdbe);
- while( p ){
- explainOneSelect(pVdbe, p);
- p = p->pNext;
- if( p==0 ) break;
- sqlite3ExplainNL(pVdbe);
- sqlite3ExplainPrintf(pVdbe, "%s\n", selectOpName(p->op));
- }
- sqlite3ExplainPrintf(pVdbe, "END");
- sqlite3ExplainPop(pVdbe);
- }
- /* End of the structure debug printing code
- *****************************************************************************/
- #endif /* defined(SQLITE_ENABLE_TREE_EXPLAIN) */
|