mysql - #1193 - 未知系统变量 'id'

Question

花了8个小时检查这个问题，但没有任何结果，有人能说错了吗？

>SELECT id FROM posts AS post_id;SET categories.id  AS category_id;  
>SELECT title, contents, date_posted, categories, name FROM posts INNER JOIN 
>categories ON categories, id = posts, cat_id ORDER BY id DESC  

出现错误 $ #1193 - 未知的系统变量“id”

我也尝试过这样的事情:

>SELECT id FROM posts AS post_id;  
>SELECT id FROM categories AS category_id;  
>SELECT COALESCE (title, contents, date_posted, categories, name) 
>FROM posts INNER JOIN categories ON categories, id = posts, cat_id
>ORDER BY id DESC

还有很多其他员工无法正常工作。

工作查询:

 >SELECT posts . p_id AS post_id, categories . c_id AS category_id,  
    >title, contents, date_posted, categories . name   
    >FROM posts  
    >INNER JOIN categories ON categories . c_id = posts . cat_id  
    >ORDER BY posts.p_id DESC;  

Answer 1

尝试将数据库中的变量名 id 更改为其他名称。 id 是保留名称。