SELECT state, COUNT(*) for clarity

Adding state to the SQL syntax to make it more clear, given that the buckets returned include the values of state AND count for each.

Closes #13597

docs/reference/getting-started.asciidoc

@@ -915,7 +915,7 @@ In SQL, the above aggregation is similar in concept to:
 
 [source,sh]
 --------------------------------------------------
-SELECT COUNT(*) from bank GROUP BY state ORDER BY COUNT(*) DESC
+SELECT state, COUNT(*) FROM bank GROUP BY state ORDER BY COUNT(*) DESC
 --------------------------------------------------
 
 And the response (partially shown):