对记录进行去重操作怎么写??

[yaningou]

假设有表abc,中有aa,bb,cc三个字段,其中aa字段唯一.
现需要将abc表中的记录根据bb字段去重,请问该怎么写?

[zakat]

delete from tbl
where rowid not in (select min(rowid) from tbl group by colb);

[guangli_zhang]

select aa,bb,cc from (select rownum rrr, abc.* from abc) x

where rrr in(select min(rrr) from (select rownum rrr, abc.* from abc) where x.bb=bb)

试试，再简单的我不会写了，好像应该用rank什么的

[zakat]

或者
delete from tbl
where rowid not in (select max(rowid) from tbl group by colb);

[zsfww1205]

delete from abc a where rowid != (select max(rowid) from abc b where a.bb = b.bb)