只筛选一个字段值相同的记录
select * from A where PDDT in(
select PDDT FROM A
group by PDDT
having count(PDDT)>1
)
筛选多个字段值相同的的记录
SELECT COUNT(*),DeptID, PDDT , DLNo , DLnore, MacNo
FROM A
GROUP BY DeptID, PDDT , DLNo , DLnore, MacNo
having count(*)>1