OpenSearch/docs/reference/query-dsl/has-parent-query.asciidoc

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[[query-dsl-has-parent-query]]
=== Has parent query
++++
<titleabbrev>Has parent</titleabbrev>
++++
Returns child documents whose <<parent-join,joined>> parent document matches a
provided query. You can create parent-child relationships between documents in
the same index using a <<parent-join,join>> field mapping.
[WARNING]
====
Because it performs a join, the `has_parent` query is slow compared to other queries.
Its performance degrades as the number of matching parent documents increases.
Each `has_parent` query in a search can increase query time significantly.
====
[[has-parent-query-ex-request]]
==== Example request
[[has-parent-index-setup]]
===== Index setup
To use the `has_parent` query, your index must include a <<parent-join,join>>
field mapping. For example:
[source,console]
----
PUT /my-index-000001
{
"mappings": {
"properties": {
"my-join-field": {
"type": "join",
"relations": {
"parent": "child"
}
},
"tag": {
"type": "keyword"
}
}
}
}
----
// TESTSETUP
[[has-parent-query-ex-query]]
===== Example query
[source,console]
----
GET /my-index-000001/_search
{
"query": {
"has_parent": {
"parent_type": "parent",
"query": {
"term": {
"tag": {
"value": "Elasticsearch"
}
}
}
}
}
}
----
[[has-parent-top-level-params]]
==== Top-level parameters for `has_parent`
`parent_type`::
(Required, string) Name of the parent relationship mapped for the
<<parent-join,join>> field.
`query`::
(Required, query object) Query you wish to run on parent documents of the
`parent_type` field. If a parent document matches the search, the query returns
its child documents.
`score`::
+
--
(Optional, Boolean) Indicates whether the <<query-filter-context,relevance
score>> of a matching parent document is aggregated into its child documents.
Defaults to `false`.
If `false`, {es} ignores the relevance score of the parent document. {es} also
assigns each child document a relevance score equal to the `query`'s `boost`,
which defaults to `1`.
If `true`, the relevance score of the matching parent document is aggregated
into its child documents' relevance scores.
--
`ignore_unmapped`::
+
--
(Optional, Boolean) Indicates whether to ignore an unmapped `parent_type` and
not return any documents instead of an error. Defaults to `false`.
If `false`, {es} returns an error if the `parent_type` is unmapped.
You can use this parameter to query multiple indices that may not contain the
`parent_type`.
--
[[has-parent-query-notes]]
==== Notes
[[has-parent-query-performance]]
===== Sorting
You cannot sort the results of a `has_parent` query using standard
<<sort-search-results,sort options>>.
If you need to sort returned documents by a field in their parent documents, use
a `function_score` query and sort by `_score`. For example, the following query
sorts returned documents by the `view_count` field of their parent documents.
[source,console]
----
GET /_search
{
"query": {
"has_parent": {
"parent_type": "parent",
"score": true,
"query": {
"function_score": {
"script_score": {
"script": "_score * doc['view_count'].value"
}
}
}
}
}
}
----