【ES】学习8-聚合1

参考资料：

https://elasticsearch.cn/book/elasticsearch_definitive_guide_2.x/_combining_the_two.html

特定概念：

桶（Buckets）满足特定条件的文档的集合

指标（Metrics）对桶内的文档进行统计计算

SELECT COUNT(color) 
FROM table
GROUP BY color 

COUNT(color) 相当于指标。

GROUP BY color 相当于桶。

聚合例子：

curl -XGET 'localhost:9200/text/_search?pretty' -d '
{"size":0,
 "aggs":
    {"popular_ports":
        {"terms":
            {"field":"port"}
        }
    }
}'

对port字段做聚合，结果名称为popular_ports。size设为0表示不关心搜索结果，结果的hits部分会是空值。

计算每种颜色车辆价格的平均值

GET /cars/transactions/_search
{
   "size" : 0,
   "aggs": {
      "colors": {
         "terms": {
            "field": "color"
         },
         "aggs": { 
            "avg_price": { 
               "avg": {
                  "field": "price" 
               }
            }
         }
      }
   }
}

嵌套桶

每个颜色的汽车制造商的分布

GET /cars/transactions/_search
{
   "size" : 0,
   "aggs": {
      "colors": {
         "terms": {
            "field": "color"
         },
         "aggs": {
            "avg_price": { 
               "avg": {
                  "field": "price"
               }
            },
            "make": { 
                "terms": {
                    "field": "make" 
                }
            }
         }
      }
   }
}

每个颜色的汽车制造商的分布，以及各个制造商生产汽车的最高和最低价格。

GET /cars/transactions/_search
{
   "size" : 0,
   "aggs": {
      "colors": {
         "terms": {
            "field": "color"
         },
         "aggs": {
            "avg_price": { "avg": { "field": "price" }
            },
            "make" : {
                "terms" : {
                    "field" : "make"
                },
                "aggs" : { 
                    "min_price" : { "min": { "field": "price"} }, 
                    "max_price" : { "max": { "field": "price"} } 
                }
            }
         }
      }
   }
}

条形图

histogram

GET /cars/transactions/_search
{
   "size" : 0,
   "aggs":{
      "price":{
         "histogram":{ 
            "field": "price",
            "interval": 20000
         },
         "aggs":{
            "revenue": {
               "sum": { 
                 "field" : "price"
               }
             }
         }
      }
   }
}

terms桶  extended_stats度量

GET /cars/transactions/_search
{
  "size" : 0,
  "aggs": {
    "makes": {
      "terms": {
        "field": "make",
        "size": 10
      },
      "aggs": {
        "stats": {
          "extended_stats": {
            "field": "price"
          }
        }
      }
    }
  }
}