OpenSearch/docs/reference/aggregations/bucket/nested-aggregation.asciidoc

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[[search-aggregations-bucket-nested-aggregation]]
=== Nested Aggregation
A special single bucket aggregation that enables aggregating nested documents.
For example, lets say we have an index of products, and each product holds the list of resellers - each having its own
price for the product. The mapping could look like:
[source,console]
--------------------------------------------------
PUT /index
{
"mappings": {
"properties" : {
"resellers" : { <1>
"type" : "nested",
"properties" : {
"name" : { "type" : "text" },
"price" : { "type" : "double" }
}
}
}
}
}
--------------------------------------------------
// TESTSETUP
<1> The `resellers` is an array that holds nested documents under the `product` object.
The following aggregations will return the minimum price products can be purchased in:
[source,console]
--------------------------------------------------
GET /_search
{
"query" : {
"match" : { "name" : "led tv" }
},
"aggs" : {
"resellers" : {
"nested" : {
"path" : "resellers"
},
"aggs" : {
"min_price" : { "min" : { "field" : "resellers.price" } }
}
}
}
}
--------------------------------------------------
// TEST[s/GET \/_search/GET \/_search\?filter_path=aggregations/]
// TEST[s/^/PUT index\/_doc\/0\?refresh\n{"name":"led", "resellers": [{"name": "foo", "price": 350.00}, {"name": "bar", "price": 500.00}]}\n/]
As you can see above, the nested aggregation requires the `path` of the nested documents within the top level documents.
Then one can define any type of aggregation over these nested documents.
Response:
[source,console-result]
--------------------------------------------------
{
...
"aggregations": {
"resellers": {
"doc_count": 0,
"min_price": {
"value": 350
}
}
}
}
--------------------------------------------------
// TESTRESPONSE[s/\.\.\.//]
// TESTRESPONSE[s/: [0-9]+/: $body.$_path/]