update语句，求助

store_day_sale表，有很多数据，mediid,strdate都相同时，把execoffice=270那一行的salenum修改成execoffice等269和等270的值之和。
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select * from store_day_sale x1 where execoffice=269 and MediId in
(select MediID from DictMedi where ChargeId = 5) and strdate between '20160101' and '20160131'
select * from store_day_sale x1 where execoffice=270 and MediId in
(select MediID from DictMedi where ChargeId = 5) and strdate between '20160101' and '20160131'

谢谢

刚才看错日期了。。应该是这个截图才对。

update store_day_sale set store_day_sale.salenum=store_day_sale.salenum+ x1.salenum
from (select MediID,strdate,salenum from store_day_sale where execoffice=269) x1
where store_day_sale.MediID=x1.MediID and store_day_sale.strdate=x1.strdate and execoffice=270
已得到同事的支持了。