[[query-dsl-bool-query]]
=== Boolean query
++++
<titleabbrev>Boolean</titleabbrev>
++++

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. Filter clauses are executed
in <<query-filter-context,filter context>>, meaning that scoring is ignored
and clauses are considered for caching.

|`should` |The clause (query) should appear in the matching document.

|`must_not` |The clause (query) must not appear in the matching
documents. Clauses are executed in <<query-filter-context,filter context>> meaning
that scoring is ignored and clauses are considered for caching. Because scoring is
ignored, a score of `0` for all documents is returned.
|=======================================================================

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,console]
--------------------------------------------------
POST _search
{
  "query": {
    "bool" : {
      "must" : {
        "term" : { "user.id" : "kimchy" }
      },
      "filter": {
        "term" : { "tags" : "production" }
      },
      "must_not" : {
        "range" : {
          "age" : { "gte" : 10, "lte" : 20 }
        }
      },
      "should" : [
        { "term" : { "tags" : "env1" } },
        { "term" : { "tags" : "deployed" } }
      ],
      "minimum_should_match" : 1,
      "boost" : 1.0
    }
  }
}
--------------------------------------------------

[[bool-min-should-match]]
==== Using `minimum_should_match`

You can use the `minimum_should_match` parameter to specify the number or
percentage of `should` clauses returned documents _must_ match.

If the `bool` query includes at least one `should` clause and no `must` or
`filter` clauses, the default value is `1`.
Otherwise, the default value is `0`.

For other valid values, see the
<<query-dsl-minimum-should-match, `minimum_should_match` parameter>>.

[[score-bool-filter]]
==== 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,console]
---------------------------------
GET _search
{
  "query": {
    "bool": {
      "filter": {
        "term": {
          "status": "active"
        }
      }
    }
  }
}
---------------------------------

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

[source,console]
---------------------------------
GET _search
{
  "query": {
    "bool": {
      "must": {
        "match_all": {}
      },
      "filter": {
        "term": {
          "status": "active"
        }
      }
    }
  }
}
---------------------------------

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,console]
---------------------------------
GET _search
{
  "query": {
    "constant_score": {
      "filter": {
        "term": {
          "status": "active"
        }
      }
    }
  }
}
---------------------------------

[[named-queries]]
==== Named queries

Each query accepts a `_name` in its top level definition. You can use named
queries to track which queries matched returned documents. If named queries are
used, the response includes a `matched_queries` property for each hit.

[source,console]
----
GET /_search
{
  "query": {
    "bool": {
      "should": [
        { "match": { "name.first": { "query": "shay", "_name": "first" } } },
        { "match": { "name.last": { "query": "banon", "_name": "last" } } }
      ],
      "filter": {
        "terms": {
          "name.last": [ "banon", "kimchy" ],
          "_name": "test"
        }
      }
    }
  }
}
----
