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一条很简单的SQL查询语句，大家帮帮忙阿
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
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
...全文
请发表友善的回复…
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elvis_gao 2007-12-08
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
kunchengking 2007-12-08
problem solved,thank you
jinboychen 2007-12-08
一楼对的
dichun 2007-12-08
没有看明白什么意思,
fa_ge 2007-12-08
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