SQL Join Ads with their Fields 将字段显示为列

Posted 2023-05-09

【中文标题】SQL Join Ads with their Fields 将字段显示为列

【英文标题】：SQL Join Ads with their Fields show fields as columns

【发布时间】：2017-08-06 07:23:04

【问题描述】：

我有一个 Ads 表和一个 Ads_field 表，当我加入时，我会为一个广告获得多行，因为它们有多个字段

有没有办法将字段显示为列？

SELECT Ads.CITY_ID,Ads.PRICE,Ads.CREATED_DATE,Ads.HAS_IMAGES, 
 Ads.TITLE, Ads.DESCRIPTION, loc_cities.name as city, CATEGORY.NAME as           
 category_name, loc_countries.country_name as 
 country,Ads_fields.field_value
 FROM Ads
 INNER JOIN loc_cities ON Ads.CITY_ID=loc_cities.id
 INNER JOIN CATEGORY ON Ads.CATEGORY_ID=CATEGORY.ID 
 INNER JOIN loc_countries ON Ads.country_code=loc_countries.ID 
 INNER JOIN Ads_fields ON Ads.ID=Ads_fields.ad_id
    WHERE CONVERT(Ads.TITLE USING utf8) LIKE '%reqqa%' 
 or CONVERT(Ads.DESCRIPTION USING utf8) LIKE '%reqqa%'
 or CONVERT(loc_cities.name USING utf8) LIKE '%reqqa%'
 or CONVERT(loc_countries.country_name USING utf8) LIKE '%reqqa%'
 or CONVERT(CATEGORY.name USING utf8) LIKE '%reqqa%'
 LIMIT 50

【问题讨论】：

php 中的 while 循环将是最简单、最快且最具可扩展性的解决方案。

绝对正确但是我想使用单个查询实现关键字搜索，while 循环最适合获取和显示数据

【参考方案1】：

一种简单的方法是将 field_value 显示为字符串逗号分隔

  SELECT 
      Ads.CITY_ID,Ads.PRICE
      , Ads.CREATED_DATE,Ads.HAS_IMAGES
      , Ads.TITLE
      , Ads.DESCRIPTION
      , loc_cities.name as city
      , CATEGORY.NAME as  category_name
      , loc_countries.country_name as country 
      , group_concat(Ads_fields.field_value)
   FROM Ads
   INNER JOIN loc_cities ON Ads.CITY_ID=loc_cities.id
   INNER JOIN CATEGORY ON Ads.CATEGORY_ID=CATEGORY.ID 
   INNER JOIN loc_countries ON Ads.country_code=loc_countries.ID 
   INNER JOIN Ads_fields ON Ads.ID=Ads_fields.ad_id
      WHERE CONVERT(Ads.TITLE USING utf8) LIKE '%reqqa%' 
   or CONVERT(Ads.DESCRIPTION USING utf8) LIKE '%reqqa%'
   or CONVERT(loc_cities.name USING utf8) LIKE '%reqqa%'
   or CONVERT(loc_countries.country_name USING utf8) LIKE '%reqqa%'
   or CONVERT(CATEGORY.name USING utf8) LIKE '%reqqa%'
   GROUP BY  Ads.CITY_ID,Ads.PRICE
      , Ads.CREATED_DATE,Ads.HAS_IMAGES
      , Ads.TITLE
      , Ads.DESCRIPTION
      , loc_cities.name 
      , CATEGORY.NAME 
      , loc_countries.country_name 
   LIMIT 50

【讨论】：

, loc_cities.name as city , CATEGORY.NAME as category_name , loc_countries.country_name as country 不起作用必须删除最后三行中的别名

@AhmedSaleh 正确。答案已更新（错误的复制和粘贴）