Php 替换列的复杂MySQL连接

保存内容信息的表-

内容

：

+----------+-------------+-------------------+--------------------------------+
| (int) id | (int) title | (int) description | (string) tags                  |
+----------+-------------+-------------------+--------------------------------+
|        1 |          12 |                18 | super, awesome, must-see       |
+-----------------------------------------------------------------------------+
|        4 |          25 |                26 | randomness, funny-stuff, cool  |
+-----------------------------------------------------------------------------+

保存翻译信息的表-

翻译

：

+-----------+---------------------------------+----------------+
| (int) tid | (text) value                    | (varchar) code |
+-----------+---------------------------------+----------------+
|        12 | Super-awesome-mustsee           | en             |
+--------------------------------------------------------------+
|        18 | <here would be the description> | en             |
+--------------------------------------------------------------+
| <more translation data that is not necessary for this xmpl.> |
+--------------------------------------------------------------+

到目前为止，我只需要为一个值连接翻译数据。。。是的，加入而不是替换：|

SELECT  `content` . * ,  `translations`.value
FROM  `content` 
JOIN  `translations` ON  `translations`.tid =  `content`.title
WHERE  `translations`.code =  'en'

我如何做到这一点

提前谢谢

没那么复杂：

SELECT
    `c`.`id`,
    `tt`.`value` AS title,
    `td`.`value` AS description,
    `c`.`tags`
FROM
    `content` `c`
LEFT JOIN 
    `translations` `tt` ON  (`tt`.`tid` = `c`.`title` AND `tt`.`code` = 'en')
LEFT JOIN 
    `translations` `td` ON  (`td`.`tid` = `c`.`description` AND `td`.`code` = 'en')

---

基本上，您需要删除

*

，并从联接表中指定精确的列及其别名。第二件事是，您必须在同一个表上创建双连接，一个用于获取标题翻译，另一个用于获取描述。要在结果中“替换”它，只需使用

value

列的别名。

这一行：在

translations

上加入

translations

。tid=

content

。title似乎是错误的：你必须在content.id上加入，而不是在title上加入……啊，谢谢，很有魅力。不知道您可以对语句进行分组。

SELECT
    `c`.`id`,
    `tt`.`value` AS title,
    `td`.`value` AS description,
    `c`.`tags`
FROM
    `content` `c`
LEFT JOIN 
    `translations` `tt` ON  (`tt`.`tid` = `c`.`title` AND `tt`.`code` = 'en')
LEFT JOIN 
    `translations` `td` ON  (`td`.`tid` = `c`.`description` AND `td`.`code` = 'en')