简单SQL语法问题（急）

[yangzi7908]

想找出表中的关键字（2个字段）的重复记录，语句为：
SELECT * FROM biao a WHERE (a.dd,a.lj)IN (SELECT dd,lj FROM biao GROUP BY dd,lj HAVING COUNT(*)>1)

运行提示第一行','附近有语法错误，SQL新手表示没法了。

[MrYangkang]

SELECT dd,lj FROM biao GROUP BY  dd,lj HAVING  COUNT(*)>1

[szm341]

SELECT * FROM biao a 
WHERE exists(SELECT 1 FROM biao
where a.dd=dd and a.lj=lj
 GROUP BY  dd,lj HAVING  COUNT(*)>1)

[MrYangkang]

SELECT * FROM biao a WHERE id in (SELECT max(id) FROM biao GROUP BY  dd,lj HAVING  COUNT(*)>1 )

[yangzi7908]

sqL版到底名不虚传啊，谢谢啦