一条很简单的SQL查询语句，大家帮帮忙阿

[kunchengking]

T1
city score
C1 90
C2 80
C3 50

T2
province score
P1 70
P2 80

T3
city province
C1 P1
C2 P2
C3 P2

希望得到各个city的分数和对应省份的分数
Result:
T4
city averageScore
C1 80
C2 80
C3 65

[fa_ge]

select a.city,(a.score+isnull(c.score,0))/2
from t1 a 
         left join 
                  t3 b
on   a.city=b.city
         left join t2 c
on   b.province=c.province       

[dichun]

没有看明白什么意思,

[jinboychen]

一楼对的

[kunchengking]

problem solved,thank you

[elvis_gao]

select a.city,(isnull(a.score,0)+isnull(c.score,0))/2
from t1 a 
left join t3 b
on a.city=b.city
left join t2 c
on b.province=c.province