---
navigation_title: "Boolean"
mapped_pages:
  - https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-bool-query.html
---

# Boolean query [query-dsl-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:

| Occur | Description |
| --- | --- |
| `must` | The clause (query) must appear in matching documents and willcontribute to the score. Each query defined under a `must` acts as a logical "AND", returning only documents that match *all* the specified queries. |
| `should` | The clause (query) should appear in the matching document. Each query defined under a `should` acts as a logical "OR", returning documents that match *any* of the specified queries. |
| `filter` | The clause (query) must appear in matching documents. However unlike`must` the score of the query will be ignored. Filter clauses are executedin [filter context](/reference/query-languages/query-dsl/query-filter-context.md), meaning that scoring is ignoredand clauses are considered for caching. Each query defined under a `filter` acts as a logical "AND", returning only documents that match *all* the specified queries. |
| `must_not` | The clause (query) must not appear in the matchingdocuments. Clauses are executed in [filter context](/reference/query-languages/query-dsl/query-filter-context.md) meaningthat scoring is ignored and clauses are considered for caching. Because scoring isignored, a score of `0` for all documents is returned. Each query defined under a `must_not` acts as a logical "NOT", returning only documents that do not match any of the specified queries. |

The `must` and `should` clauses function as logical AND, OR operators, contributing to the scoring of results. However, these results will not be cached for faster retrieval. In contrast, the `filter` and `must_not` clauses are used to include or exclude results without impacting the score, unless used within a `constant_score` query.

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.

```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
    }
  }
}
```

## Using `minimum_should_match` [bool-min-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 [`minimum_should_match` parameter](/reference/query-languages/query-dsl/query-dsl-minimum-should-match.md).


## Scoring with `bool.filter` [score-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:

```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.

```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.

```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.

::::{note}
Supplying duplicate `_name` values in the same request results in undefined behavior. Queries with duplicate names may overwrite each other. Query names are assumed to be unique within a single request.
::::


```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"
        }
      }
    }
  }
}
```

The request parameter named `include_named_queries_score` controls whether scores associated with the matched queries are returned or not. When set, the response includes a `matched_queries` map that contains the name of the query that matched as a key and its associated score as the value.

::::{warning}
Note that the score might not have contributed to the final score of the document, for instance named queries that appear in a filter or must_not contexts, or inside a clause that ignores or modifies the score like `constant_score` or `function_score_query`.
::::


```console
GET /_search?include_named_queries_score
{
  "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"
        }
      }
    }
  }
}
```

::::{note}
This functionality reruns each named query on every hit in a search response. Typically, this adds a small overhead to a request. However, using computationally expensive named queries on a large number of hits may add significant overhead. For example, named queries in combination with a `top_hits` aggregation on many buckets may lead to longer response times.
::::