select count(distinct a.字段) as acount
from a inner join b on a.字段=b.字段

select sum(b.字段) as bsum
from a inner join b on a.字段=b.字段
group by b.字段

------解决方案--------------------
你算聚合函数那里连from都没有的？不抱错吗？

------解决方案--------------------
晕，这都能不报错？把你表结构给出来，最好给点数据吧。抽时间帮你谢谢select(select count(SubCode)from Speed
  where convert(varchar(7),BeginDate,120) = '2012-09' )as spCount,
  (select SUM(B.kiloDay)where convert(varchar(7),billdate,120) = '2012-09')as kiloSum,B.SubCode
  from Kilo B
  left join Speed A
  on A.SubCode = B.SubCode
  where convert(varchar(7),billdate,120) = '2012-09'
  group by B.SubCode,A.SubCode,convert(varchar(7),billdate,120)