elasticsearch - 通过聚合，是否可以将数组属性的所有值从所有分组的文档合并到合并的文档中？

Question

我的文档格式类似于以下内容:

[
{
  "name": "fred",
  "title": "engineer",
  "division_id": 20
  "skills": [
     "walking",
     "talking"
  ]
},
{
  "name": "ed",
  "title": "ticket-taker",
  "division_id": 20
  "skills": [
     "smiling"
  ]
}
]

我想运行aggs查询，以显示该部门的完整技能:即，

{

   "aggs":{
      "distinct_skills":{
         "cardinality":{
            "field":"division_id"
         }
      }
   },
    "_source":{
      "includes":[
         "division_id",
         "skills"
      ]
   }
}

..的结果如下:

{
  "division_id": 20,
  "skills": [
     "walking",
     "talking",
     "smiling"
  ]
}

我知道我可以检索inner_hits并“手动”遍历列表和合并值。我认为如果可以查询它会更好。

Answer 1

只需管道两个Terms Aggregation查询，如下所示:

POST <your_index_name>/_search
{
  "size": 0,
  "aggs": {
    "my_division_ids": {
      "terms": {
        "field": "division_id",
        "size": 10
      },
      "aggs": {
        "my_skills": {
          "terms": {
            "field": "skills",          <---- If it is not keyword field use `skills.keyword` field if using dynamic mapping. 
            "size": 10
          }
        }
      }
    }
  }
}

以下是示例响应:

响应:

{
  "took" : 490,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "my_division_ids" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : 20,                            <---- division_id
          "doc_count" : 2,
          "my_skills" : {
            "doc_count_error_upper_bound" : 0,
            "sum_other_doc_count" : 0,
            "buckets" : [                        <---- Skills
              {
                "key" : "smiling",
                "doc_count" : 1
              },
              {
                "key" : "talking",
                "doc_count" : 1
              },
              {
                "key" : "walking",
                "doc_count" : 1
              }
            ]
          }
        }
      ]
    }
  }
}

希望这可以帮助!