求一sql语句,高手请进!!急!!

[tt007]

两张表,一张客户(user)表,一张联系(admin)表,以uid(客户id)关联,联系过的客户,就在联系表中记录信息,现在想查询user表中有,联系表中没有的客户,也就是没有联系过的客户!!!

[loveflea]

select a.* from admin a left join user u on a.id=u.uid where u.uid is null;

[tt007]

楼上的好象反了啊,我查的数据是user表中的啊!!

[tt007]

我写了一句,但速度很慢!!!
select uid from user where uid not in (select uid from admin)

[aidingy]

典型的左联接查询语句