以sCardNum分组,取出最大时间的记录
select * from cards where srcvouchdate in (select MAX(srcvouchdate) from UserList group by sCardNum)
select * from cards a
where not exists
(select 1 from cards where acardnum=a.acardnum and srcvouchdate>a.srcvouchdate)
selecct ct.* from (select sCardNum num,max(日期列) dt from cards group by sCardNum) tmp left join cards ct on ct.sCardNum= tmp.num and ct.日期列=tmp.dt
select * from cards a
where not exists
(select 1 from cards where acardnum=a.acardnum and srcvouchdate>a.srcvouchdate)
select * from cards where scardnum in(select scardnum,max(srcvouchdate) from cards group scardnum);