insert c(UserName,UserLl,YwMoney)
select a.userName,a.UserLl,isnull(b.YwMoney,0)
from a
left join (select UserName,sum(YwMoney) as YwMoney from b group by UserName) b
on a.UserName=b.UserName

------解决方案--------------------
探讨

SQL code
insert c(UserName,UserLl,YwMoney)
select a.userName,a.UserLl,isnull(b.YwMoney,0)
from a
left join (select UserName,sum(YwMoney) as YwMoney from b group by UserName) b
on a.UserName=b.Use……


------解决方案--------------------
SQL code

select t1.userName,t1.UserLl,YwMoney=sum(YwMoney) into C from A t1 inner join B t2 on t1.userNmae=t2.userName group by t1.userName,t1.UserLl

------解决方案--------------------
SQL code
insert into 
   c
select
   *
from
   (
    select  userName,UserLl,0 as YwMoneyfrom a
    union all
    select UserName,'',sum(YwMoney) as YwMoney from b group by UserName)t

------解决方案--------------------
探讨

SQL code

insert into 
   c
select
   *
from
   (
    select  userName,UserLl,0 as YwMoneyfrom a
    union all
    select UserName,'',sum(YwMoney) as YwMoney from b group by UserName)t