表a：userid，username
表b：userid，incost，
表c:userid,outcost
现在要查出这样一个结果集：userid ,username,sum(incost),sum(outcost)
我的sql如下：
select a.userid,(a.username),sum(b.incost) as sumincost,sum(c.outcost) as sumoutcost
from xxzx_user_zyl a,xxzx_incost b, xxzx_outcost c
where a.userid=b.userid and b.userid=c.userid
group by a.userid,a.username
结果查出来的结果总是不对，求高人指导
------解决方案--------------------
userid是否有重复的，
这个应该用full join 吧
------解决方案--------------------
- SQL code
select a.userid, a.username, sum(b.incost) sumincost, sum(c.outcost) sumoutcost from xxzx_user_zyl a,xxzx_incost b, xxzx_outcost cwhere a.userid=b.userid and b.userid=c.userid group by a.userid,a.username
------解决方案--------------------
- SQL code
SELECT userid,username,Sum(incost) over (PARTITION BY userid,username) as incost,Sum(outcost) over (PARTITION BY userid,username) as outcost FROM xxzx_user_zyl a,xxzx_incost b, xxzx_outcost cWHERE a.userid=b.userid(+)AND a.userid=c.userid(+)
------解决方案--------------------
select a.userid, a.username, sum(b.incost) sumincost, sum(c.outcost) sumoutcost from xxzx_user_zyl a,xxzx_incost b, xxzx_outcost c where a.userid=b.userid(+) and A.userid=c.userid(+) group by a.userid,a.username
是以A表为准,进行外关联