即使第二个表上的行不存在，也要正确连接

Question

我想加入两个表，即使第二个表没有匹配。

表用户：

uid | name
1     dude1
2     dude2

表帐户：

uid | accountid | name
1     1           account1

我想要的表：

uid  | username | accountname
1      dude1      account1
2      dude2      NULL

我正在尝试的查询：

SELECT user.uid as uid, user.name as username, account.name as accountname
FROM user RIGHT JOIN account ON user.uid=accout.uid

我得到了什么：

uid  | username | accountname
1      dude1      account1

Answer 1

请改用Left Join

SELECT user.uid as uid, user.name as username, account.name as accountname
FROM user LEFT JOIN account ON user.uid=accountid.uid

Answer 2

尝试使用LEFT JOIN查询

SELECT user.uid as uid, user.name as username, account.name as accountname
FROM user 
LEFT JOIN account 
ON user.uid=accout.uid

我想看看JOIN查询的这种直观表示

Answer 3

右连接保留第二个表中的所有结果（它将所有结果保留在右侧表中），您需要左连接，或者在连接子句中交换用户和帐户的位置。

SELECT user.uid as uid, user.name as username, account.name as accountname
FROM user LEFT JOIN account ON user.uid=account.uid

我相信应该这样做。