Query and filter context

By default, Elasticsearch sorts matching search results by relevance score, which measures how well each document matches a query.

The relevance score is a positive floating point number, returned in the _score metadata field of the search API. The higher the _score, the more relevant the document. While each query type can calculate relevance scores differently, score calculation also depends on whether the query clause is run in a query or filter context.

In the query context, a query clause answers the question “How well does this document match this query clause?” Besides deciding whether or not the document matches, the query clause also calculates a relevance score in the _score metadata field.

Query context is in effect whenever a query clause is passed to a query parameter, such as the query parameter in the search API.

A filter answers the binary question “Does this document match this query clause?”. The answer is simply "yes" or "no". Filtering has several benefits:

Filters are particularly effective for querying structured data and implementing "must have" criteria in complex searches.

Structured data refers to information that is highly organized and formatted in a predefined manner. In the context of Elasticsearch, this typically includes:

Unlike full-text fields, structured data has a consistent, predictable format, making it ideal for precise filtering operations.

Common filter applications include:

Filter context applies when a query clause is passed to a filter parameter, such as:

Filters optimize query performance and efficiency, especially for structured data queries and when combined with full-text searches.

Below is an example of query clauses being used in query and filter context in the search API. This query will match documents where all of the following conditions are met:

$params = [
    'body' => [
        'query' => [
            'bool' => [
                'must' => [
                    [
                        'match' => [
                            'title' => 'Search',
                        ],
                    ],
                    [
                        'match' => [
                            'content' => 'Elasticsearch',
                        ],
                    ],
                ],
                'filter' => [
                    [
                        'term' => [
                            'status' => 'published',
                        ],
                    ],
                    [
                        'range' => [
                            'publish_date' => [
                                'gte' => '2015-01-01',
                            ],
                        ],
                    ],
                ],
            ],
        ],
    ],
];
$response = $client->search($params);

resp = client.search(
    query={
        "bool": {
            "must": [
                {
                    "match": {
                        "title": "Search"
                    }
                },
                {
                    "match": {
                        "content": "Elasticsearch"
                    }
                }
            ],
            "filter": [
                {
                    "term": {
                        "status": "published"
                    }
                },
                {
                    "range": {
                        "publish_date": {
                            "gte": "2015-01-01"
                        }
                    }
                }
            ]
        }
    },
)
print(resp)

response = client.search(
  body: {
    query: {
      bool: {
        must: [
          {
            match: {
              title: 'Search'
            }
          },
          {
            match: {
              content: 'Elasticsearch'
            }
          }
        ],
        filter: [
          {
            term: {
              status: 'published'
            }
          },
          {
            range: {
              publish_date: {
                gte: '2015-01-01'
              }
            }
          }
        ]
      }
    }
  }
)
puts response

res, err := es.Search(
	es.Search.WithBody(strings.NewReader(`{
	  "query": {
	    "bool": {
	      "must": [
	        {
	          "match": {
	            "title": "Search"
	          }
	        },
	        {
	          "match": {
	            "content": "Elasticsearch"
	          }
	        }
	      ],
	      "filter": [
	        {
	          "term": {
	            "status": "published"
	          }
	        },
	        {
	          "range": {
	            "publish_date": {
	              "gte": "2015-01-01"
	            }
	          }
	        }
	      ]
	    }
	  }
	}`)),
	es.Search.WithPretty(),
)
fmt.Println(res, err)

const response = await client.search({
  query: {
    bool: {
      must: [
        {
          match: {
            title: "Search",
          },
        },
        {
          match: {
            content: "Elasticsearch",
          },
        },
      ],
      filter: [
        {
          term: {
            status: "published",
          },
        },
        {
          range: {
            publish_date: {
              gte: "2015-01-01",
            },
          },
        },
      ],
    },
  },
});
console.log(response);

GET /_search
{
  "query": { 
    "bool": { 
      "must": [
        { "match": { "title":   "Search"        }},
        { "match": { "content": "Elasticsearch" }}
      ],
      "filter": [ 
        { "term":  { "status": "published" }},
        { "range": { "publish_date": { "gte": "2015-01-01" }}}
      ]
    }
  }
}