Mysql如何在连接相同的表中选择

Question

SELECT users.* FROM users
JOIN users AS parent
ON parent.username = 'Joe'
WHERE users.ip = parent.ip;

这是对的吗？

如何在同一个表格中选择：

SELECT article.* FROM article
JOIN users
ON users.username = 'Joe' OR users.ip = (????? maybe users.ip)
WHERE article.owner = users.username;

感谢。

Answer 1

我认为你必须交换ON和WHERE子句的内容：

SELECT * FROM article
JOIN users
ON article.owner = users.username 
WHERE users.username = 'Joe' OR users.ip = (????? maybe users.ip);

ON子句根据两个表连接的条件确定