[[children-agg]] === Children Aggregation Parent-child supports a http://bit.ly/1xtpjaz[`children` aggregation] as ((("aggregations", "children aggregation")))((("children aggregation")))((("parent-child relationship", "children aggregation")))a direct analog to the `nested` aggregation discussed in <<nested-aggregation>>. A parent aggregation (the equivalent of `reverse_nested`) is not supported. This example demonstrates how we could determine the favorite hobbies of our employees by country: [source,json] ------------------------- GET /company/branch/_search?search_type=count { "aggs": { "country": { "terms": { <1> "field": "country" }, "aggs": { "employees": { "children": { <2> "type": "employee" }, "aggs": { "hobby": { "terms": { <3> "field": "employee.hobby" } } } } } } } } ------------------------- <1> The `country` field in the `branch` documents. <2> The `children` aggregation joins the parent documents with their associated children of type `employee`. <3> The `hobby` field from the `employee` child documents.