SQL筛选不重复数据
表一A中有重复数据，其中字段为：kddh,tjdate，表二B中字段为：kddh,thdate
筛选表A中kddh不重复的数据并且取tjdate最新的哪条记录但在表二B中kddh却不存在的记录
[解决办法]

SELECT kddh,MAX(tjdate)
FROM A
WHERE NOT EXISTS(SELECT 1 FROM B WHERE A.kddh=B.kddh)
GROUP BY kddh

保险起见，lz还是给出数据和要求的结果吧
[解决办法]
select kddh,max(tjdate)
from A
where kddh not in (select kddh from B)
group by kddh