请教一个sql语句? select userid,sum(usermoney) as usermoneyfrom ( select * from a union all select * from b ) cgroup by userid 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 select a.userid,sum(isnull(a.usermoney,0)+isnull(b.usermoney,0)) usermoneyfrom a left outer join b on a.userid=b.useridgroup by a.userid select a.userid,usermoney=isnull(a.usermoney,0)+isnull(b.usermoney,0)from 表a a left join 表b b on a.userid=b.userid select userid,sum(usermoney) usermoneyfrom ( select * from a union select * from b ) cgroup by userid zjcxc(: 邹建 :) ,您实在是太厉害了,真想有机会和您聊聊 select a.userid aid,a.usermoney auser,b.userid bid,b.usermoney buser from 表a a left join 表b b on a.userid=b.userid显示的结果是不是这样:aid auser bid buser1 10 1 102 30 2 53 40 NULL NULL4 10 NULL NULL我一直对外连接的左右连接不能好好的理解,请问我的显示结果对吗,为什么? select a.userid,usermoney=isnull(a.usermoney,0)+isnull(b.usermoney,0)from 表a a left join 表b b on a.userid=b.userid select userid,'usermoney'=usermoney+isnull((select usermoney from b where a.userid=b.userid),0)from a select a.userid aid,(a.usermoney+ isnull(b.usermoney,0)) buser from 表a a left join 表b b on a.userid=b.userid select a.userid, usermoney=isnull(a.usermoney,0)+isnull(b.usermoney,0) from 表a a left join 表b b on a.userid=b.userid where {condition state} reporting service 部署出现的问题,求助 sql2000发生错误,不能建表还原附加【在线】急! 开始新建跟踪失败!!帮忙看下了 使用SQL语句还原数据库出现的问题 求助,关于表批量更新的基础问题 关于删除重复记录的问题 请教:如果SQL语句中使用的变量含有“'”,请问如何处理? 入门级菜鸟问题 新手求教问题~~ 求一个并列结果集的SQL语句 游标问题请求(马可、邹建)给予帮助 菜鸟问题,SQL-SERVER的客户端和服务器端各负责什么?
from a left outer join b on a.userid=b.userid
group by a.userid
from 表a a left join 表b b on a.userid=b.userid
from ( select * from a
union
select * from b
) c
group by userid
from 表a a left join 表b b on a.userid=b.userid
显示的结果是不是这样:aid auser bid buser
1 10 1 10
2 30 2 5
3 40 NULL NULL
4 10 NULL NULL
我一直对外连接的左右连接不能好好的理解,请问我的显示结果对吗,为什么?
from 表a a left join 表b b on a.userid=b.userid
from a
from 表a a left join 表b b on a.userid=b.userid
usermoney=isnull(a.usermoney,0)+isnull(b.usermoney,0)
from 表a a left join
表b b on a.userid=b.userid
where {condition state}