Mysql子查询别名

Question

当我在where子句中使用子查询别名时，我得到了未知列错误：

SELECT name, 
(SELECT id FROM category c2 WHERE c2.parent_id=23) children 
FROM category c1 WHERE c1.id IN children;

有人能说出为什么这段代码不起作用吗？

Answer 1

反过来说：

SELECT name, 
FROM category c1 
WHERE c1.id IN (SELECT id FROM category c2 WHERE c2.parent_id=23);

Answer 2

我认为你可以在没有子选择的情况下进行查询

 select a.name, b.id as children  
 from category as a
 inner join category b on ( a.c1.id = b.id  and b.parent_id = 23 );