问题：设表T中有五个字段A，B，C，D，ID，其中ID字段是为自动增量整型字段(唯一值)。业务数据生成时有重复插入现象，现需对A、B、C、D四字段完全一样的脏数据进行清理，要求设计一SQL语句，对四个字段完全一样的记录，仅保留ID最小的一条，其余作删除处理。 DELETE FROM T WHERE [ID] IN ( select [ID] from T where A in (select A from T Group By A,B,C,D Having count(*)>1) and [ID]<> (select min(ID) as minID from T Group By A,B,C,D Having count(*)>1) ) 更正： delete from T where T.ID not in (select min(ID) from T group by T.A,T.B,T.C,T.D)
