sql问题？

显示全部楼层 · 2005-10-30 17:05:33

decode函数怎么使用？书上怎么没有呀！
select name
from test
group by name
having select name
from test
group by name
having sum(decode(number,1,-1,3,-1,5,-1,number)) = -3

哪们帮俺解释一下sum(decode(number,1,-1,3,-1,5,-1,number)) 这一段是啥意思好吗？
sorry!初学者，别见笑......

千问 · 2005-10-30 17:05:33

decode(number,1,-1,3,-1,5,-1,number)=
if number=1 then
number=-1
elsif number = 3 then
number = -1
elsif number = 5 then
number = -1
end if

千问 · 2005-10-30 17:05:33

错了。
应该是：
if number=1 then
decode(number,1,-1,3,-1,5,-1,number)=-1
elsif number = 3 then
decode(number,1,-1,3,-1,5,-1,number)=-1
elsif number = 5 then
decode(number,1,-1,3,-1,5,-1,number)= -1
else
decode(number,1,-1,3,-1,5,-1,number)=number
end if