138 lines
3.6 KiB
Plaintext
138 lines
3.6 KiB
Plaintext
[[query-dsl-bool-query]]
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=== Boolean query
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++++
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<titleabbrev>Boolean</titleabbrev>
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++++
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A query that matches documents matching boolean combinations of other
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queries. The bool query maps to Lucene `BooleanQuery`. It is built using
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one or more boolean clauses, each clause with a typed occurrence. The
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occurrence types are:
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[cols="<,<",options="header",]
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|=======================================================================
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|Occur |Description
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|`must` |The clause (query) must appear in matching documents and will
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contribute to the score.
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|`filter` |The clause (query) must appear in matching documents. However unlike
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`must` the score of the query will be ignored. Filter clauses are executed
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in <<query-filter-context,filter context>>, meaning that scoring is ignored
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and clauses are considered for caching.
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|`should` |The clause (query) should appear in the matching document.
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|`must_not` |The clause (query) must not appear in the matching
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documents. Clauses are executed in <<query-filter-context,filter context>> meaning
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that scoring is ignored and clauses are considered for caching. Because scoring is
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ignored, a score of `0` for all documents is returned.
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|=======================================================================
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The `bool` query takes a _more-matches-is-better_ approach, so the score from
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each matching `must` or `should` clause will be added together to provide the
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final `_score` for each document.
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[source,console]
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--------------------------------------------------
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POST _search
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{
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"query": {
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"bool" : {
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"must" : {
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"term" : { "user" : "kimchy" }
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},
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"filter": {
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"term" : { "tag" : "tech" }
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},
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"must_not" : {
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"range" : {
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"age" : { "gte" : 10, "lte" : 20 }
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}
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},
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"should" : [
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{ "term" : { "tag" : "wow" } },
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{ "term" : { "tag" : "elasticsearch" } }
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],
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"minimum_should_match" : 1,
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"boost" : 1.0
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}
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}
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}
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--------------------------------------------------
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[[score-bool-filter]]
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==== Scoring with `bool.filter`
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Queries specified under the `filter` element have no effect on scoring --
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scores are returned as `0`. Scores are only affected by the query that has
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been specified. For instance, all three of the following queries return
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all documents where the `status` field contains the term `active`.
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This first query assigns a score of `0` to all documents, as no scoring
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query has been specified:
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[source,console]
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---------------------------------
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GET _search
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{
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"query": {
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"bool": {
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"filter": {
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"term": {
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"status": "active"
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}
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}
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}
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}
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}
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---------------------------------
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This `bool` query has a `match_all` query, which assigns a score of `1.0` to
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all documents.
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[source,console]
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---------------------------------
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GET _search
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{
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"query": {
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"bool": {
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"must": {
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"match_all": {}
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},
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"filter": {
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"term": {
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"status": "active"
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}
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}
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}
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}
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}
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---------------------------------
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This `constant_score` query behaves in exactly the same way as the second example above.
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The `constant_score` query assigns a score of `1.0` to all documents matched
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by the filter.
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[source,console]
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---------------------------------
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GET _search
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{
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"query": {
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"constant_score": {
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"filter": {
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"term": {
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"status": "active"
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}
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}
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}
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}
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}
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---------------------------------
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==== Using named queries to see which clauses matched
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If you need to know which of the clauses in the bool query matched the documents
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returned from the query, you can use
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<<request-body-search-queries-and-filters,named queries>> to assign a name to
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each clause.
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