elasticsearch之查詢的兩種方式

目錄

• 前言
• 准備數據
• 查詢字符串
• 結構化查詢

• 返回主目錄

前言

簡單的沒挑戰，來點復雜的，比如查看來自顧家的都有哪些人怎么查呢？elasticsearch提供兩種查詢方式：

• 查詢字符串(query string)，簡單查詢，就像是像傳遞URL參數一樣去傳遞查詢語句，被稱為簡單搜索或查詢字符串(query string)搜索。
• 另外一種是通過DSL語句來進行查詢，被稱為DSL查詢(Query DSL),DSL是Elasticsearch提供的一種豐富且靈活的查詢語言，該語言以json請求體的形式出現，通過restful請求與Elasticsearch進行交互。

准備數據

PUT zhifou/doc/1
{
  "name":"顧老二",
  "age":30,
  "from": "gu",
  "desc": "皮膚黑、武器長、性格直",
  "tags": ["黑", "長", "直"]
}

PUT zhifou/doc/2
{
  "name":"大娘子",
  "age":18,
  "from":"sheng",
  "desc":"膚白貌美，嬌憨可愛",
  "tags":["白", "富","美"]
}

PUT zhifou/doc/3
{
  "name":"龍套偏房",
  "age":22,
  "from":"gu",
  "desc":"mmp，沒怎么看，不知道怎么形容",
  "tags":["造數據", "真","難"]
}


PUT zhifou/doc/4
{
  "name":"石頭",
  "age":29,
  "from":"gu",
  "desc":"粗中有細，狐假虎威",
  "tags":["粗", "大","猛"]
}

PUT zhifou/doc/5
{
  "name":"魏行首",
  "age":25,
  "from":"廣雲台",
  "desc":"仿佛兮若輕雲之蔽月,飄飄兮若流風之回雪,mmp，最后竟然沒有嫁給顧老二！",
  "tags":["閉月","羞花"]
}

查詢字符串

GET zhifou/doc/_search?q=from:gu

還是使用GET命令，通過_serarch查詢，查詢條件是什么呢？條件是from屬性是gu家的人都有哪些。最后，別忘了_search和from屬性中間的英文分隔符?。

結果如下：

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 3,
    "max_score" : 0.6931472,
    "hits" : [
      {
        "_index" : "zhifou",
        "_type" : "doc",
        "_id" : "4",
        "_score" : 0.6931472,
        "_source" : {
          "name" : "石頭",
          "age" : 29,
          "from" : "gu",
          "desc" : "粗中有細，狐假虎威",
          "tags" : [
            "粗",
            "大",
            "猛"
          ]
        }
      },
      {
        "_index" : "zhifou",
        "_type" : "doc",
        "_id" : "1",
        "_score" : 0.2876821,
        "_source" : {
          "name" : "顧老二",
          "age" : 30,
          "from" : "gu",
          "desc" : "皮膚黑、武器長、性格直",
          "tags" : [
            "黑",
            "長",
            "直"
          ]
        }
      },
      {
        "_index" : "zhifou",
        "_type" : "doc",
        "_id" : "3",
        "_score" : 0.2876821,
        "_source" : {
          "name" : "龍套偏房",
          "age" : 22,
          "from" : "gu",
          "desc" : "mmp，沒怎么看，不知道怎么形容",
          "tags" : [
            "造數據",
            "真",
            "難"
          ]
        }
      }
    ]
  }
}

我們來重點說下hits，hits是返回的結果集——所有from屬性為gu的結果集。重點中的重點是_score得分，得分是什么呢？根據算法算出跟查詢條件的匹配度，匹配度高得分就高。后面再說這個算法是怎么回事。

結構化查詢

我們現在使用DSL方式，來完成剛才的查詢，查看來自顧家的都有哪些人。

GET zhifou/doc/_search
{
  "query": {
    "match": {
      "from": "gu"
    }
  }
}

上例，查詢條件是一步步構建出來的，將查詢條件添加到match中即可，而match則是查詢所有from字段的值中含有gu的結果就會返回。
當然結果沒啥變化：

{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 3,
    "max_score" : 0.6931472,
    "hits" : [
      {
        "_index" : "zhifou",
        "_type" : "doc",
        "_id" : "4",
        "_score" : 0.6931472,
        "_source" : {
          "name" : "石頭",
          "age" : 29,
          "from" : "gu",
          "desc" : "粗中有細，狐假虎威",
          "tags" : [
            "粗",
            "大",
            "猛"
          ]
        }
      },
      {
        "_index" : "zhifou",
        "_type" : "doc",
        "_id" : "1",
        "_score" : 0.2876821,
        "_source" : {
          "name" : "顧老二",
          "age" : 30,
          "from" : "gu",
          "desc" : "皮膚黑、武器長、性格直",
          "tags" : [
            "黑",
            "長",
            "直"
          ]
        }
      },
      {
        "_index" : "zhifou",
        "_type" : "doc",
        "_id" : "3",
        "_score" : 0.2876821,
        "_source" : {
          "name" : "龍套偏房",
          "age" : 22,
          "from" : "gu",
          "desc" : "mmp，沒怎么看，不知道怎么形容",
          "tags" : [
            "造數據",
            "真",
            "難"
          ]
        }
      }
    ]
  }
}

---

see also：[Elasticsearch查詢規則（一）match和term](https://www.jianshu.com/p/eb30eee13923) that's all