Has parent query
Returns 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.
To 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"
}
}
}
}
GET /my-index-000001/_search
{
"query": {
"has_parent": {
"parent_type": "parent",
"query": {
"term": {
"tag": {
"value": "Elasticsearch"
}
}
}
}
}
}
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_typefield. 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 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_typeand not return any documents instead of an error. Defaults tofalse.
If false, Elasticsearch 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.
You 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"
}
}
}
}
}
}