elasticsearch/docs/reference/query-dsl/bool-query.asciidoc

[[query-dsl-bool-query]]
=== Bool Query

A query that matches documents matching boolean combinations of other
queries. The bool query maps to Lucene `BooleanQuery`. It is built using
one or more boolean clauses, each clause with a typed occurrence. The
occurrence types are:

[cols="<,<",options="header",]
|=======================================================================
|Occur |Description
|`must` |The clause (query) must appear in matching documents and will
contribute to the score.

|`filter` |The clause (query) must appear in matching documents. However unlike
`must` the score of the query will be ignored.

|`should` |The clause (query) should appear in the matching document. In
a boolean query with no `must` clauses, one or more `should` clauses
must match a document. The minimum number of should clauses to match can
be set using the
<<query-dsl-minimum-should-match,`minimum_should_match`>>
parameter.

|`must_not` |The clause (query) must not appear in the matching
documents.
|=======================================================================

[IMPORTANT]
.Bool query in filter context
========================================================================
If this query is used in a filter context and it has `should`
clauses then at least one `should` clause is required to match.
========================================================================

The bool query also supports `disable_coord` parameter (defaults to
`false`). Basically the coord similarity computes a score factor based
on the fraction of all query terms that a document contains. See Lucene
`BooleanQuery` for more details.

The `bool` query takes a _more-matches-is-better_ approach, so the score from
each matching `must` or `should` clause will be added together to provide the 
final `_score` for each document.

[source,js]
--------------------------------------------------
{
    "bool" : {
        "must" : {
            "term" : { "user" : "kimchy" }
        },
        "filter": {
            "term" : { "tag" : "tech" }
        },
        "must_not" : {
            "range" : {
                "age" : { "from" : 10, "to" : 20 }
            }
        },
        "should" : [
            {
                "term" : { "tag" : "wow" }
            },
            {
                "term" : { "tag" : "elasticsearch" }
            }
        ],
        "minimum_should_match" : 1,
        "boost" : 1.0
    }
}
--------------------------------------------------

==== Scoring with `bool.filter` 

Queries specified under the `filter` element have no effect on scoring --
scores are returned as `0`.  Scores are only affected by the query that has
been specified.  For instance, all three of the following queries return 
all documents where the `status` field contains the term `active`. 

This first query assigns a score of `0` to all documents, as no scoring
query has been specified: 

[source,json]
---------------------------------
GET _search
{
  "query": {
    "bool": {
      "filter": {
        "term": {
          "status": "active"
        }
      }
    }
  }
}
---------------------------------
// AUTOSENSE

This `bool` query has a `match_all` query, which assigns a score of `1.0` to 
all documents.

[source,json]
---------------------------------
GET _search
{
  "query": {
    "bool": {
      "query": {
        "match_all": {}
      },
      "filter": {
        "term": {
          "status": "active"
        }
      }
    }
  }
}
---------------------------------
// AUTOSENSE

This `constant_score` query behaves in exactly the same way as the second example above.  
The `constant_score` query assigns a score of `1.0` to all documents matched
by the filter. 

[source,json]
---------------------------------
GET _search
{
  "query": {
    "constant_score": {
      "filter": {
        "term": {
          "status": "active"
        }
      }
    }
  }
}
---------------------------------
// AUTOSENSE