IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Nested aggregation
editNested aggregation
editA 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:
response = client.indices.create( index: 'products', body: { mappings: { properties: { resellers: { type: 'nested', properties: { reseller: { type: 'keyword' }, price: { type: 'double' } } } } } } ) puts response
PUT /products { "mappings": { "properties": { "resellers": { "type": "nested", "properties": { "reseller": { "type": "keyword" }, "price": { "type": "double" } } } } } }
The following request adds a product with two resellers:
response = client.index( index: 'products', id: 0, refresh: true, body: { name: 'LED TV', resellers: [ { reseller: 'companyA', price: 350 }, { reseller: 'companyB', price: 500 } ] } ) puts response
PUT /products/_doc/0?refresh { "name": "LED TV", "resellers": [ { "reseller": "companyA", "price": 350 }, { "reseller": "companyB", "price": 500 } ] }
The following request returns the minimum price a product can be purchased for:
response = client.search( index: 'products', size: 0, body: { query: { match: { name: 'led tv' } }, aggregations: { resellers: { nested: { path: 'resellers' }, aggregations: { min_price: { min: { field: 'resellers.price' } } } } } } ) puts response
GET /products/_search?size=0 { "query": { "match": { "name": "led tv" } }, "aggs": { "resellers": { "nested": { "path": "resellers" }, "aggs": { "min_price": { "min": { "field": "resellers.price" } } } } } }
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:
{ ... "aggregations": { "resellers": { "doc_count": 2, "min_price": { "value": 350.0 } } } }
You can use a filter
sub-aggregation to return results for a specific reseller.
response = client.search( index: 'products', size: 0, body: { query: { match: { name: 'led tv' } }, aggregations: { resellers: { nested: { path: 'resellers' }, aggregations: { filter_reseller: { filter: { bool: { filter: [ { term: { 'resellers.reseller' => 'companyB' } } ] } }, aggregations: { min_price: { min: { field: 'resellers.price' } } } } } } } } ) puts response
GET /products/_search?size=0 { "query": { "match": { "name": "led tv" } }, "aggs": { "resellers": { "nested": { "path": "resellers" }, "aggs": { "filter_reseller": { "filter": { "bool": { "filter": [ { "term": { "resellers.reseller": "companyB" } } ] } }, "aggs": { "min_price": { "min": { "field": "resellers.price" } } } } } } } }
The search returns:
{ ... "aggregations": { "resellers": { "doc_count": 2, "filter_reseller": { "doc_count": 1, "min_price": { "value": 500.0 } } } } }