RT 例一张表如下
A B
a1 b1
a1 b1
a1 b2
如何查询出重复记录a1 b1
如何删除其中一条重复记录
分都悬赏了！
sql 多字段 数据
------解决方案--------------------
查询的语句
select * from t
where (A,B) in (select A,B from t group by A,B having count(*) > 1)
加一列自增长列 id 后删除的语句如下
select * from t
where (A,B) in (select A,B from t group by A,B having count(*) > 1)
and id not in (select min(id) from t group by A,B having count(*) > 1)