MySQL的join使用，

MySQL的join使用，

#内连接
select * from auth_user u inner join auth_group g on u.id = g.id;

#左连接
select * from auth_user a left join auth_group b on a.id = b.id;

#右连接
select * from auth_user a right join auth_group b on a.id = b.id;

#左链接-内连接
select * from auth_user a left join auth_group b on a.id = b.id where b.id is null;

#右连接-内连接
select * from auth_user a right join auth_group b on a.id = b.id where b.id is null;

#MySQL外连接不让使用full join 或者full outer join