急求一个SQL语句，

[aspnet_2012]

A表：
PNO,UP,UP1,UP2,UP3,UP4,UP5,FLAG
p1  1,2,3,4,5,0
p2  2,3,4,2,3,1
p3  5,2,3,2,1,0

B表：
SITE,PNO,CST
s1   p1,8
s2   p1,6

现在要得到一个结果集：当A表的FLAG为0的时候判断B表 是否有 PNO相同的记录，并且SITE为s1。
有就更新UP,UP1,UP2,UP3,UP4,UP5 的值为 B表的CST的值。

最终结果如下：

C表：
PNO,UP,UP1,UP2,UP3,UP4,UP5
p1  8, 8, 8, 8, 8
p2  2,3,4,2,3
p3  5,2,3,2,1

[aspnet_2012]

错了，不是要更新A表，是要产生一个新的结果集。表C

[Oraclers]

select ,A.PNO ,CASE WHEN A.FLAG=0 and Q.SITE='S1' THEN B.CST ELSE A.UP END as UP ,CASE WHEN A.FLAG=0 and Q.SITE='S1' THEN B.CST ELSE A.UP1 END as UP1 ,CASE WHEN A.FLAG=0 and Q.SITE='S1' THEN B.CST ELSE A.UP2 END as UP2 ,CASE WHEN A.FLAG=0 and Q.SITE='S1' THEN B.CST ELSE A.UP3 END as UP3 ,CASE WHEN A.FLAG=0 and Q.SITE='S1' THEN B.CST ELSE A.UP4 END as UP4 ,CASE WHEN A.FLAG=0 and Q.SITE='S1' THEN B.CST ELSE A.UP5 END as UP5 INTO C from A left join (SELECT * FROM B WHERE [SITE]='S1') Q on A.PNO=Q.PNO

[快溜]

update A set UP=B.CST,UP1=B.CST,UP2=B.CST,UP3=B.CST,UP4=B.CST,UP5=B.CST from A,B where A.PNO=B.PNO and A.FLAG=0

[chuifengde]

UPDATE A1 SET UP=CST,UP1=CST,UP2=CST,UP3=CST,UP4=CST,UP5=CST
FROM A A1 INNOR JOIN B ON A1.PNO=B.PNO WHERE FLAG=0 AND SITE='s1'