表一:A1
aid username
1 张三
2 李四
3 王五
4 孙李
表二:B2
bid aid money
1 1 100.00
2 2 50.00
3 1 50.00
4 1 20.00
结果表:
aid username moneytotal
1 张三 170.00
2 李四 50.00
3 王五 0.00
4 孙李 0.00
------解决方案--------------------
SELECT a1.aid,a1.username,ISNULL(b.[money],0.00)[moneytotal]
FROM a1 LEFT JOIN (SELECT aid,SUM([money])[money] FROM b2 GROUP BY aid) b2 ON a1.aid=b2.aid
------解决方案--------------------

------解决方案--------------------
试试这个:
select aid,
username,
(select SUM(money) from B2 where a1.aid = b2.aid) moneytotal
from a1
------解决方案--------------------
修改一下:
select aid,
username,
isnull((select SUM(money) from B2 where a1.aid = b2.aid),0) moneytotal
from a1