OpenSearch/docs/reference/query-dsl/queries/nested-query.asciidoc

[[query-dsl-nested-query]]
=== Nested Query

Nested query allows to query nested objects / docs (see
<<mapping-nested-type,nested mapping>>). The
query is executed against the nested objects / docs as if they were
indexed as separate docs (they are, internally) and resulting in the
root parent doc (or parent nested mapping). Here is a sample mapping we
will work with:

[source,js]
--------------------------------------------------
{
    "type1" : {
        "properties" : {
            "obj1" : {
                "type" : "nested"
            }
        }
    }
}
--------------------------------------------------

And here is a sample nested query usage:

[source,js]
--------------------------------------------------
{
    "nested" : {
        "path" : "obj1",
        "score_mode" : "avg",
        "query" : {
            "bool" : {
                "must" : [
                    {
                        "match" : {"obj1.name" : "blue"}
                    },
                    {
                        "range" : {"obj1.count" : {"gt" : 5}}
                    }
                ]
            }
        }
    }
}
--------------------------------------------------

The query `path` points to the nested object path, and the `query` (or
`filter`) includes the query that will run on the nested docs matching
the direct path, and joining with the root parent docs. Note that any
fields referenced inside the query must use the complete path (fully 
qualified).

The `score_mode` allows to set how inner children matching affects
scoring of parent. It defaults to `avg`, but can be `sum`, `max` and
`none`.

Multi level nesting is automatically supported, and detected, resulting
in an inner nested query to automatically match the relevant nesting
level (and not root) if it exists within another nested query.