再一sql语句怎么写？

[xjis00]

表tab如下
a b c d .....
--- ----- ----- ---- -----
1 w a d .....
2 w b d .....
3 w a d .....
4 w c d .....
5 w a e .....
.
.
.
我怎样让他只显示为
a b c d .....
--- ----- ----- ---- -----
1 w a d .....
2 w b d .....
4 w c d .....
5 w a e .....
.
.
即bcd列相同的给去出了 不知道怎么写这个sql语句？

[njjianguogu]

select tab.* from tab,(select b,c,d from tab group by b,c,d) A where tab.b = A.b and tab.c = A.c and tab.d = A.d

[mittee]

用下面的试一下

SELECT DISTINCT *
FROM tab

[佣工7001]

select * from tab where not exists b=c and c=d and b=d;

[佣工7001]

上面错了，应该是
select * from tab where (b<>c or c<>d or b<>d);

[bflovesnow]

select * from tb where id not in(select min(id) id from tb group by b,c,d)