如何计算下面的平均价 求助

Question

select ctno,blockcode,avg(blockcode) as avgprice
from 表
group by ctno,blockcode

Answer 1

select ctno, blockcode ,avg(num*price)
from 表 
group by ctno, blockcode

Answer 2

1.
select ctno,blockcode,num,price,b.avgprice
from tablename a,(select sum(num*price*1.00)/(case sum(num) when 0 then 1 else sum(num) end) as avgprice from tablename group by ctno,blockcode) b
where a.ctno=b.ctno and a.blockcode=b.blockcode
2.
select ctno,blockcode,sum(num*price*1.00)/(case sum(num) when 0 then 1 else sum(num) end) as avgprice
from tablename
group by ctno,blockcode

Answer 3

哎呀，错啦。
select ctno, blockcode ,sum(num*price) /sum(num) 
from 表 
group by ctno, blockcode