Elasticsearch Top hits Aggregati

Top hits Aggregation 较为常用的统计。获取到每组前n条数据。相当于sql 中 group by 后取出前n条

例子：取100组，每组只要第一条。为了简便没用order和_source，请自行测试他们。

GET test_index/_search?search_type=count
{
  "query": {
    "match_all": {}
  },
  "aggs": {
    "all_interests": {
      "terms": {
        "field": "department_id",
        "size": 100
      },
      "aggs": {
        "top_tag_hits": {
          "top_hits": {
            "size": 1
          }
        }
      }
    }
  }
}~~~