http://bbs.csdn.net/topics/350135010
参考
select *
from a aa left join
b bb on aa.id=bb.cid and bb.adddate=(select max(adddate) from b where cid=bb.cid)
自己写
Left join rechargeSheet rs on rs.PaymentCode=o.order_code and rs.CreationTime=(select MAX(CreationTime) from rechargeSheet where PaymentCode=rs.PaymentCode)