Has parent query
editHas parent query
editReturns child documents whose joined parent document matches a provided query. You can create parent-child relationships between documents in the same index using a join field mapping.
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.
Example request
editIndex setup
editTo use the has_parent
query, your index must include a join
field mapping. For example:
PUT /my-index-000001 { "mappings": { "properties": { "my-join-field": { "type": "join", "relations": { "parent": "child" } }, "tag": { "type": "keyword" } } } }
Example query
editGET /my-index-000001/_search { "query": { "has_parent": { "parent_type": "parent", "query": { "term": { "tag": { "value": "Elasticsearch" } } } } } }
Top-level parameters for has_parent
edit-
parent_type
- (Required, string) Name of the parent relationship mapped for the 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 relevance score of a matching parent document is aggregated into its child documents. Defaults to
false
.If
false
, Elasticsearch ignores the relevance score of the parent document. Elasticsearch also assigns each child document a relevance score equal to thequery
'sboost
, which defaults to1
.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 tofalse
.If
false
, Elasticsearch returns an error if theparent_type
is unmapped.You can use this parameter to query multiple indices that may not contain the
parent_type
.
Notes
editSorting
editYou cannot sort the results of a has_parent
query using standard
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.
GET /_search { "query": { "has_parent": { "parent_type": "parent", "score": true, "query": { "function_score": { "script_score": { "script": "_score * doc['view_count'].value" } } } } } }