Top Hits Aggregation

需求： 对每个用户发表的博客进行分组

造数据

PUT /blogs/_doc/2
{
  "title":"learn words",
  "content":"learning elasticsearch",
  "userInfo":{
    "userId":2,
    "username":"jack"
  }
}

PUT /blogs/_doc/3
{
  "title":"learn hello",
  "content":"learning hello",
  "userInfo":{
    "userId":3,
    "username":"jim"
  }
}

PUT /blogs/_doc/4
{
  "title":"learn lucy",
  "content":"learning chinese",
  "userInfo":{
    "userId":5,
    "username":"lucy"
  }
}

PUT /blogs/_doc/5
{
  "title":"learn two",
  "content":"learning english",
  "userInfo":{
    "userId":5,
    "username":"two"
  }
}

PUT /blogs/_doc/6
{
  "title":"learn six",
  "content":"learning six",
  "userInfo":{
    "userId":5,
    "username":"six"
  }
}

#对每个用户发表的博客进行分组,取前5篇的标题

GET /blogs/_search
{
  "size":0,
  "aggs":{
    "group_by_userName":{
      "terms":{
        "field":"userInfo.username.keyword"
      },
      "aggs":{
        "top_blog":{
          "top_hits":{
            "_source":{
              "includes":"title"
            },
            "size":5
          }
        }
      }
    }
  }
}

结果

{
  "took" : 789,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 6,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "group_by_userName" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : "jack",
          "doc_count" : 1,
          "top_blog" : {
            "hits" : {
              "total" : {
                "value" : 1,
                "relation" : "eq"
              },
              "max_score" : 1.0,
              "hits" : [
                {
                  "_index" : "blogs",
                  "_type" : "_doc",
                  "_id" : "2",
                  "_score" : 1.0,
                  "_source" : {
                    "title" : "learn words"
                  }
                }
              ]
            }
          }
        },
        {
          "key" : "jim",
          "doc_count" : 1,
          "top_blog" : {
            "hits" : {
              "total" : {
                "value" : 1,
                "relation" : "eq"
              },
              "max_score" : 1.0,
              "hits" : [
                {
                  "_index" : "blogs",
                  "_type" : "_doc",
                  "_id" : "3",
                  "_score" : 1.0,
                  "_source" : {
                    "title" : "learn hello"
                  }
                }
              ]
            }
          }
        },
        {
          "key" : "lucy",
          "doc_count" : 1,
          "top_blog" : {
            "hits" : {
              "total" : {
                "value" : 1,
                "relation" : "eq"
              },
              "max_score" : 1.0,
              "hits" : [
                {
                  "_index" : "blogs",
                  "_type" : "_doc",
                  "_id" : "4",
                  "_score" : 1.0,
                  "_source" : {
                    "title" : "learn lucy"
                  }
                }
              ]
            }
          }
        },
        {
          "key" : "six",
          "doc_count" : 1,
          "top_blog" : {
            "hits" : {
              "total" : {
                "value" : 1,
                "relation" : "eq"
              },
              "max_score" : 1.0,
              "hits" : [
                {
                  "_index" : "blogs",
                  "_type" : "_doc",
                  "_id" : "6",
                  "_score" : 1.0,
                  "_source" : {
                    "title" : "learn six"
                  }
                }
              ]
            }
          }
        },
        {
          "key" : "two",
          "doc_count" : 1,
          "top_blog" : {
            "hits" : {
              "total" : {
                "value" : 1,
                "relation" : "eq"
              },
              "max_score" : 1.0,
              "hits" : [
                {
                  "_index" : "blogs",
                  "_type" : "_doc",
                  "_id" : "5",
                  "_score" : 1.0,
                  "_source" : {
                    "title" : "learn two"
                  }
                }
              ]
            }
          }
        },
        {
          "key" : "夏明",
          "doc_count" : 1,
          "top_blog" : {
            "hits" : {
              "total" : {
                "value" : 1,
                "relation" : "eq"
              },
              "max_score" : 1.0,
              "hits" : [
                {
                  "_index" : "blogs",
                  "_type" : "_doc",
                  "_id" : "1",
                  "_score" : 1.0,
                  "_source" : {
                    "title" : "盛夏的果实"
                  }
                }
              ]
            }
          }
        }
      ]
    }
  }
}