【ES】学习9-聚合2

转载

mob604756fc093d 2017-06-15 16:42:00

文章标签 elasticsearch 字段嵌套 sed 其他 文章分类 代码人生

按时间统计：date_histogram

GET /cars/transactions/_search
{
   "size" : 0,
   "aggs": {
      "sales": {
         "date_histogram": {
            "field": "sold",
            "interval": "month", 
            "format": "yyyy-MM-dd" 
         }
      }
   }
}

注意，这种写法在数字字段没有问题，但是在文本字段使用之前必须先把对应字段的fielddata设为true才可以。否则会报错：

"caused_by" : {
      "type" : "illegal_argument_exception",
      "reason" : "Fielddata is disabled on text fields by default. Set fielddata=true on [name] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."
    }

注意，设置了fielddata会消耗大量内存。

返回空buckets：设置参数 min_doc_count

限制返回时间范围：设置参数 extended_bounds

GET /cars/transactions/_search
{
   "size" : 0,
   "aggs": {
      "sales": {
         "date_histogram": {
            "field": "sold",
            "interval": "month",
            "format": "yyyy-MM-dd",
            "min_doc_count" : 0, 
            "extended_bounds" : { 
                "min" : "2014-01-01",
                "max" : "2014-12-31"
            }
         }
      }
   }
}

扩展例子：

GET /cars/transactions/_search
{
   "size" : 0,
   "aggs": {
      "sales": {
         "date_histogram": {
            "field": "sold",
            "interval": "quarter", 
            "format": "yyyy-MM-dd",
            "min_doc_count" : 0,
            "extended_bounds" : {
                "min" : "2014-01-01",
                "max" : "2014-12-31"
            }
         },
         "aggs": {
            "per_make_sum": {
               "terms": {
                  "field": "make"
               },
               "aggs": {
                  "sum_price": {
                     "sum": { "field": "price" } 
                  }
               }
            },
            "total_sum": {
               "sum": { "field": "price" } 
            }
         }
      }
   }
}