PostgreSQL Json字段作為查詢條件的解決方案

讀前思考：

   　　你沒想到解決辦法？PostgreSQL 數據庫本身就支持還是另有解決辦法？

          使用JOSNB作為字段類型。現在開始,,,,,,,,,,,,,,,,,,

json如下：

"rule":{
    "tags": {
        "target": "logon"
    },
    "time": "2019-11-15 10:00:00",
    "method": "scheduled",
    "source": "backend",
    "aliases": [],
    "sendType": "tag",
    "registrationIds": []
}

現在我想獲取 rule 字段 里面的  sendType="tag",那現在怎么搞？

代碼如下：

  #####Mybatis#####
  <select id="selectPushDataList" resultMap="BaseResultMap" parameterType="com.jpc.JpushData" >
    SELECT
      <include refid="Base_Column_List" />
    FROM
        jp_push jpt
    <where>
      delete_flag=1
      and (rule::json->>'sendType')::text = 'tag'
      <if test="name != null and name !=''" >
        and name =#{name,jdbcType=VARCHAR}
      </if>
      ORDER BY
        create_time ASC
         LIMIT ${pageSize} OFFSET ${(currentPage - 1) * pageSize}
    </where>
  </select>
  
  ####PostgreSQL  SQL####
      SELECT
        uuid,create_user,create_time,update_user,update_time,delete_flag,NAME,type,push,rule, STATUS 
    FROM
        jp_push jpt 
    WHERE
        jpt.delete_flag = 1 
        AND ( jpct.rule :: json ->> 'sendType' ) :: text = 'tag' 
        AND jpt.NAME = 'testname' 
    ORDER BY jpt.create_time ASC LIMIT 20 OFFSET 0

結果如下：

再看如下的json串：

--如何獲取title，description呢--------

----------pre- zh en app----------
"pre": {
  "zh": {
     "app": {
       "title": "test",
       "description": "test",
       "images": [
           "https://www.baidu.com/",
           "https://www.baidu.com/1"
   ]
}
},
"en": {
 "app": {
  "title": "test",
   "description": "test",
   "images": [
    "https://www.baidu.com/",
   "https://www.baidu.com/1"
  ]
  }
}
---------------pre zh en web------------------------------------
"pre": {
  "zh": {
   "web": {
   "title": "test",
   "description": "test",
    "images": [
      "https://www.baidu.com/",
      "https://www.baidu.com/1"
   ]
  }
},
"en": {
"web": {
  "title": "test",
  "description": "test",
     "images": [
       "https://www.baidu.com/",
       "https://www.baidu.com/1"
    ]
   }
  }
}

如何寫sql？ 把語言和端作為一個變量傳進去...

SELECT
　　　　uuid,　address,pre,
　　　　pre :: json -> '${lunguage}' -> '${device}' ->> 'title' AS title,
　　　　pre :: json -> '${lunguage}' -> '${device}' ->> 'description' AS description 
FROM
　　"ban".test j

 獲取 zh-web不為空的內容：

lunguage 傳  zh,device傳 web

SELECT
　　　　uuid,address,　pre,
　　　　pre :: json -> '${lunguage}' -> '${device}' ->> 'title' AS title,
　　　　pre :: json -> '${lunguage}' -> '${device}' ->> 'description' AS description 
FROM
　　"ban".test j  where  pre :: json -> '${lunguage}' -> '${device}' is not null

獲取 zh-web-images數組里面的第一個圖片信息不為空的內容：

SELECT 
     uuid,address,　pre,
　　　　pre :: json -> '${lunguage}' -> '${device}' ->> 'title' AS title,
　　　　pre :: json -> '${lunguage}' -> '${device}' ->> 'description' AS description,
       pre :: json -> '${lunguage}' -> '${device}' ->>0::'images' AS images
FROM 
   　"ban".test j where pre :: json -> '${lunguage}' -> '${device}' is not null

 

 總結：PostgreSQL 本身就支持以json作為sql的查詢條件。