Elasticsearch 查詢結果分組統計,聚合檢索(group by stats)

AR414發表於2021-03-05
Elasticsearch

前言

在使用Elasticsearch做搜尋的時候，經常會碰到需要將搜尋的結果分好類別，每個只取指定數量給到前端，舉個例子：鬥魚直播平臺搜尋

Elasticsearch 查詢結果分組統計,聚合檢索(group by stats)

假設搜尋結果就分三個組：相關主播, 相關視訊, 相關UP主
再假設所有組的資料都儲存在同一個索引

假設索引結構

data: 綜合搜尋展示的簡要資料
content: 搜尋關鍵詞集合, 例如: “盧本偉,55開,世界第一小魚人,英雄聯盟”
type: 類別, 例如: 主播,視訊,UP主
weight: 權重

{
  "settings": {
    "number_of_shards": 1
  },
  "mappings": {
    "properties": {
      "data": {
        "type": "object"
      },
      "content": {
        "type": "text",
        "analyzer": "ik_max_word",
        "search_analyzer": "ik_smart"
      },
      "type": {
        "type": "keyword"
      },
      "weight": {
        "type": "keyword"
      }
    }
  }
}

查詢結果分組統計

  1. 將結果按類別分組，每個組都按權重進行倒序，每組只展示前6個，只保留data資料項

    {
"size": 0,
"query": {
 "match_phrase": {
   "content": "大神"
 }
},
"aggs": {
 "ret": {
   "terms": {
     "field": "type",
     "size": "3"
   },
   "aggs": {
     "type": {
       "terms": {
         "field": "type",
         "size": 3
       },
       "aggs": {
         "top": {
           "top_hits": {
             "sort": [
               {
                 "weight": {
                   "order": "desc"
                 }
               }
             ],
             "_source": [
               "data"
             ],
             "size": 6
           }
         }
       }
     }
   }
 }
}
}

  2. 如果每個類別都需要單獨定製引數，比如主播按權重倒序, 視訊按釋出時間倒序

    {
"size": 0,
"query": {
 "match_phrase": {
   "content": "大神"
 }
},
"aggs": {
 "anchor": { //主播
   "filter": {
     "bool": {
       "must": {
         "term": {
           "type": "1"
         }
       }
     }
   },
   "aggs": {
     "type": {
       "terms": {
         "field": "type",
         "size": 1
       },
       "aggs": {
         "top": {
           "top_hits": {
             "sort": [
               {
                 "weight": {
                   "order": "desc"
                 }
               }
             ],
             "_source": [
               "data"
             ],
             "size": 6
           }
         }
       }
     }
   }
 },
 "video": { //視訊
   "filter": {
     "bool": {
       "must": {
         "term": {
           "type": "2"
         }
       }
     }
   },
   "aggs": {
     "type": {
       "terms": {
         "field": "type",
         "size": 1
       },
       "aggs": {
         "top": {
           "top_hits": {
             "sort": [
               {
                 "create_time": {
                   "order": "desc"
                 }
               }
             ],
             "_source": [
               "data"
             ],
             "size": 6
           }
         }
       }
     }
   }
 }
}
}

結語

Elasticsearch的功能非常強大,個人偏向於能在Elasticsearch上完成的事不會放在php程式碼中處理, 如果你有更便捷更好的寫法歡迎分享

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