为什么此 SQL 代码会给出错误 1066(非唯一表/别名:'user')? [英] Why does this SQL code give error 1066 (Not unique table/alias: 'user')?

问题描述

这是我的表结构:

错误信息是:

#1066 - 不是唯一的表/别名:'user'

#1066 - Not unique table/alias: 'user'

以下是我的代码.

SELECT article.* , section.title, category.title, user.name, user.name
FROM article
INNER JOIN section ON article.section_id = section.id
INNER JOIN category ON article.category_id = category.id
INNER JOIN user ON article.author_id = user.id
LEFT JOIN user ON article.modified_by = user.id
WHERE article.id = '1'

推荐答案

第二次加入时需要给用户表一个别名

You need to give the user table an alias the second time you join to it

例如

SELECT article . * , section.title, category.title, user.name, u2.name 
FROM article 
INNER JOIN section ON article.section_id = section.id 
INNER JOIN category ON article.category_id = category.id 
INNER JOIN user ON article.author_id = user.id 
LEFT JOIN user u2 ON article.modified_by = u2.id 
WHERE article.id = '1'

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