Metrics Aggregations [指标聚合]

avg aggregation

cardinality aggregation

max aggregation

min aggregation

sum aggregation

value count aggregation

extended stats aggregation

Bucket Aggregations [桶聚合]

Missing Aggregation

统计某个不存在字段notExistsField的数量

GET index/type/_search
{
  "query": {
    "match_all": {}
  },
  "aggs": {
    "missing_example" : {
      "missing": {
        "field": "notExistsField"
      }
    }
  }
}

Range Aggregation

范围聚合，统计每个范围内的文档数量

GET index/type/_search
{
  "query": {
    "match_all": {}
  },
  "aggs": {
    "range_example": {
      "range": {
        "field": "amount",
        "keyed": true,
        "ranges": [
          {
            "to": 10
          },
          {
            "from": 11,
            "to": 20
          },
          {
            "from": 21,
            "to": 30
          }
        ]
      }
    }
  }
}

Terms Aggregation

类似于MySQL的 group by，按sex统计文档数量

GET index/type/_search
{
  "query": {
    "match_all": {}
  },
  "aggs": {
    "terms_example": {
      "terms": {
        "field": "sex",
        "size": 10
      }
    }
  }
}

Significant Terms Aggregation

与Terms的区别: 返回结果中多了doc_count、bg_count

GET index/type/_search
{
  "size": 0, 
  "query": {
    "match_all": {}
  },
  "aggs": {
    "terms_example": {
      "significant_terms": {
        "field": "state"
      }
    }
  }
} 
// 返回结果
{
  "took": 14,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 264729,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "terms_example": {
      "doc_count": 264729,    //文档数量
      "bg_count": 266199,     //未知
      "buckets": [
        {
          "key": "1",
          "doc_count": 103122,  //key为1的文档数量
          "score": 0.0021440541483472653,
          "bg_count": 103127   //未知
        }
      ]
    }
  }
}