小编典典

像GROUP BY AND HAVING这样的SQL

elasticsearch

我想获取满足一定条件的组数。用SQL术语来说,我想在Elasticsearch中执行以下操作。

SELECT COUNT(*) FROM
(
   SELECT
    senderResellerId,
    SUM(requestAmountValue) AS t_amount
   FROM
    transactions
   GROUP BY
    senderResellerId
   HAVING
    t_amount > 10000 ) AS dum;

到目前为止,我可以通过术语聚合将senderResellerId分组。但是,当我应用过滤器时,它无法按预期工作。

弹性请求

{
  "aggregations": {
    "reseller_sale_sum": {
      "aggs": {
        "sales": {
          "aggregations": {
            "reseller_sale": {
              "sum": {
                "field": "requestAmountValue"
              }
            }
          }, 
          "filter": {
            "range": {
              "reseller_sale": { 
                "gte": 10000
              }
            }
          }
        }
      }, 
      "terms": {
        "field": "senderResellerId", 
        "order": {
          "sales>reseller_sale": "desc"
        }, 
        "size": 5
      }
    }
  }, 
  "ext": {}, 
  "query": {  "match_all": {} }, 
  "size": 0
}

实际反应

{
  "took" : 21,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "failed" : 0
  },
  "hits" : {
    "total" : 150824,
    "max_score" : 0.0,
    "hits" : [ ]
  },
  "aggregations" : {
    "reseller_sale_sum" : {
      "doc_count_error_upper_bound" : -1,
      "sum_other_doc_count" : 149609,
      "buckets" : [
        {
          "key" : "RES0000000004",
          "doc_count" : 8,
          "sales" : {
            "doc_count" : 0,
            "reseller_sale" : {
              "value" : 0.0
            }
          }
        },
        {
          "key" : "RES0000000005",
          "doc_count" : 39,
          "sales" : {
            "doc_count" : 0,
            "reseller_sale" : {
              "value" : 0.0
            }
          }
        },
        {
          "key" : "RES0000000006",
          "doc_count" : 57,
          "sales" : {
            "doc_count" : 0,
            "reseller_sale" : {
              "value" : 0.0
            }
          }
        },
        {
          "key" : "RES0000000007",
          "doc_count" : 134,
          "sales" : {
            "doc_count" : 0,
            "reseller_sale" : {
              "value" : 0.0
            }
          }
        }
          }
        }
      ]
    }
  }
}

从上面的响应中可以看到,它正在返回代理商,但是 reseller_sale 聚合结果为零。

更多细节在这里


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2020-06-22

共1个答案

小编典典

实现类似HAVING的行为

您可以使用一种pipeline aggregations,即存储桶选择器聚合。查询如下所示:

POST my_index/tdrs/_search
{
   "aggregations": {
      "reseller_sale_sum": {
         "aggregations": {
            "sales": {
               "sum": {
                  "field": "requestAmountValue"
               }
            },
            "max_sales": {
               "bucket_selector": {
                  "buckets_path": {
                     "var1": "sales"
                  },
                  "script": "params.var1 > 10000"
               }
            }
         },
         "terms": {
            "field": "senderResellerId",
            "order": {
               "sales": "desc"
            },
            "size": 5
         }
      }
   },
   "size": 0
}

将以下文档放入索引后:

  "hits": [
     {
        "_index": "my_index",
        "_type": "tdrs",
        "_id": "AV9Yh5F-dSw48Z0DWDys",
        "_score": 1,
        "_source": {
           "requestAmountValue": 7000,
           "senderResellerId": "ID_1"
        }
     },
     {
        "_index": "my_index",
        "_type": "tdrs",
        "_id": "AV9Yh684dSw48Z0DWDyt",
        "_score": 1,
        "_source": {
           "requestAmountValue": 5000,
           "senderResellerId": "ID_1"
        }
     },
     {
        "_index": "my_index",
        "_type": "tdrs",
        "_id": "AV9Yh8TBdSw48Z0DWDyu",
        "_score": 1,
        "_source": {
           "requestAmountValue": 1000,
           "senderResellerId": "ID_2"
        }
     }
  ]

查询的结果是:

"aggregations": {
      "reseller_sale_sum": {
         "doc_count_error_upper_bound": 0,
         "sum_other_doc_count": 0,
         "buckets": [
            {
               "key": "ID_1",
               "doc_count": 2,
               "sales": {
                  "value": 12000
               }
            }
         ]
      }
   }

即仅那些senderResellerId累计销售额为的者>10000

数桶

要实现等效功能,SELECT COUNT(*) FROM (... HAVING)可以结合使用桶脚本聚合总和桶聚合。尽管似乎没有直接的方法来计算bucket_selector实际选择了多少个存储桶,但我们可以定义一个bucket_script产生01取决于条件的sum_bucket产生它的sum

POST my_index/tdrs/_search
{
   "aggregations": {
      "reseller_sale_sum": {
         "aggregations": {
            "sales": {
               "sum": {
                  "field": "requestAmountValue"
               }
            },
            "max_sales": {
               "bucket_script": {
                  "buckets_path": {
                     "var1": "sales"
                  },
                  "script": "if (params.var1 > 10000) { 1 } else { 0 }"
               }
            }
         },
         "terms": {
            "field": "senderResellerId",
            "order": {
               "sales": "desc"
            }
         }
      },
      "max_sales_stats": {
         "sum_bucket": {
            "buckets_path": "reseller_sale_sum>max_sales"
         }
      }
   },
   "size": 0
}

输出将是:

   "aggregations": {
      "reseller_sale_sum": {
         "doc_count_error_upper_bound": 0,
         "sum_other_doc_count": 0,
         "buckets": [
            ...
         ]
      },
      "max_sales_stats": {
         "value": 1
      }
   }

所需的存储桶数位于中max_sales_stats.value

重要注意事项

我必须指出两件事:

  1. 该功能是实验性的(从ES 5.6开始,它仍是实验性的,尽管它是在2.0.0-beta1中添加的。)
  2. 管道聚合应用于先前的聚合结果:

管道聚合工作于其他聚合而不是文档集所产生的输出,从而将信息添加到输出树中。

这意味着bucket_selector将在上的terms聚合结果之后和之后应用聚合senderResellerId。例如,如果聚合定义senderResellerId不止size一个terms,则不会使用来获得集合中的
所有 id sum(sales) > 10000,而只会获取出现在terms聚合输出中的id
。考虑使用排序和/或设置足够的size参数。

这也适用于第二种情况,COUNT() (... HAVING)该情况仅计算聚合输出中实际存在的那些存储桶。

如果此查询太重或存储桶数太大,请考虑对数据进行规范化或将此总和直接存储在文档中,以便可以使用普通range查询来实现您的目标。

希望有帮助!

2020-06-22