Elastic_Terms 內容分類統計

Terms 按字段的值進行分類，並計算出doc_count，

bucket聚合 相似於 group by

經常使用統計 分類並出現頻率高的，並進一步挖出，計算出想要的數據。

參考資料

    https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-terms-aggregation.html    

1.批量插入數據

   curl -XPOST 127.0.0.1:9200/cars/transactions/_bulk --data-binary @cars.json   

{ "index": {}}
{ "price" : 10000, "color" : "red", "make" : "honda", "sold" : "2014-10-28" }
{ "index": {}}
{ "price" : 20000, "color" : "red", "make" : "honda", "sold" : "2014-11-05" }
{ "index": {}}
{ "price" : 30000, "color" : "green", "make" : "ford", "sold" : "2014-05-18" }
{ "index": {}}
{ "price" : 15000, "color" : "blue", "make" : "toyota", "sold" : "2014-07-02" }
{ "index": {}}
{ "price" : 12000, "color" : "green", "make" : "toyota", "sold" : "2014-08-19" }
{ "index": {}}
{ "price" : 20000, "color" : "red", "make" : "honda", "sold" : "2014-11-05" }
{ "index": {}}
{ "price" : 80000, "color" : "red", "make" : "bmw", "sold" : "2014-01-01" }
{ "index": {}}
{ "price" : 25000, "color" : "blue", "make" : "ford", "sold" : "2014-02-12" }

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2.哪一種顏色的車賣的最好
  http://192.168.1.10:9200/cars/
       _search?search_type=count //並不關心搜索結果,只關心統計，使用的search_type是count

 1 { "aggs": {
 3     "color": {
 4       "terms": {             //定義了一個terms類型的桶，它針對color字段聚合,terms桶會動態地爲每個它遇到的不重複的詞條建立一個新的桶
 5         "field": "color",
 6         "size": 50,                //返回結果大小
 7         "min_doc_count": 1,         //控制最小計數 大於1才顯示
 8         "order": {"_count": "asc" } //排序方式
11       }
12     }
13   }
14 }

  //每一個桶中的key對應的是在color字段中找到的不重複的詞條。它同時也包含了一個doc_count，用來表示包含了該詞條的文檔數量。
  //響應包含了一個桶列表，每一個桶都對應着一個不重複的顏色(好比，紅色或者綠色)。每一個桶也包含了「掉入」該桶中的文檔數量。好比，有4輛紅色的車

3.每種顏色汽車的平均價格是多少?

{  "aggs": {
    "color": {
      "terms": {
        "field": "color",
        "size": 50,
        "min_doc_count": 1,
        "order": {  "avg_price": "asc"    }    //按平均價格排序
       },
       "aggs": {           //添加了一個新的aggs層級（聚合層）avg 指標嵌套在terms桶中，每種顏色都計算一個平均值
        "avg_price": {
          "avg": {  "field": "price"  }
        }
      }
    }
  }
}

返回每一個顏色汽車的個數及平均價格

4.每種顏色的汽車的製造商分佈信息?

{"aggs": {
    "color": {
      "terms": {
        "field": "color",
        "size": 50,
        "min_doc_count": 1,
        "order": {"avg_price": "asc" }
      },
      "aggs": {
        "avg_price": {
          "avg": { "field": "price"      }
        },
        "make": { //添加了新聚合make，它是一個terms類型的桶(嵌套在名爲colors的terms桶中)。這意味着會根據數據集建立不重複的(color, make)組合
          "terms": { "field": "make"  }
        }
      }
    }
  }
}

4.再添加 每一個製造商 最低和最高價格?

{ "aggs": {
    "color": {
      "terms": {
        "field": "color",
        "size": 50,
        "min_doc_count": 1,
        "order": {
          "avg_price": "asc"
        }
      },
      "aggs": {
        "avg_price": {
          "avg": {
            "field": "price"
          }
        },
        "make": {
          "terms": { "field": "make"},
          "aggs": {
            "min_price": { "min": { "field": "price"       }       },
            "max_price": { "max": {   "field": "price"   }       }
          }
        }
      }
    }
  }
}

5.再添加 每一個製造商 價格列表?

{
  "aggs": {
    "color": {
      "terms": {
        "field": "color",
        "size": 50,
        "min_doc_count": 1,
        "order": {
          "avg_price": "asc"
        }
      },
      "aggs": {
        "avg_price": {
          "avg": {
            "field": "price"
          }
        },
        "make": {
          "terms": {
            "field": "make"
          },
          "aggs": {
            "price": {
              "terms": {
                "field": "price"
              }
            },
            "min_price": {
              "min": {
                "field": "price"
              }
            },
            "max_price": {
              "max": {
                "field": "price"
              }
            }
          }
        }
      }
    }
  }
}

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