请高手帮忙，SQL问题

[lxqlogo0]

create table #temp1
(
Flag int,
F1 decimal(18,2),
F2 decimal(18,2),
F3 decimal(18,2)
)

insert into #temp1
select 1 as Flag,2000 as F1,4000 as F2,5000 as F3
union
select 2 as Flag,360 as F1,300 as F2,400 as F3
union
select 3 as Flag,null as F1,null as F2,null as F3

select * from #temp1
drop table #temp1

想计算Flag 每列（F1,F2,F3）的值等于Flag=2的除以Flag=1的行。
即：Flag=3的行的值为：
F1:360/2000,
F2:300/4000,
F3:400/5000
请问用SQL怎么实现，谢谢！

[thinclient]

没明白,顶吧

[thinclient]

计算...的行
还是选出这些行?
不明白

[lxqlogo0]

计算Flag=3 的行，用Flag=2的行除以Flag=1的行

[chunchun0017]

select
F1=(select f1 from #temp1 where Flag=2)/(select f1 from #temp1 where Flag=1),
F2=(select f2 from #temp1 where Flag=2)/(select f2 from #temp1 where Flag=1),
F3=(select f3 from #temp1 where Flag=2)/(select f3 from #temp1 where Flag=1)
from #temp1 where Flag=3

[chunchun0017]

create table #temp1
(
Flag int,
F1 decimal(18,2),
F2 decimal(18,2),
F3 decimal(18,2)
)

insert into #temp1
select 1 as Flag,2000 as F1,4000 as F2,5000 as F3
union
select 2 as Flag,360 as F1,300 as F2,400 as F3
union
select 3 as Flag,null as F1,null as F2,null as F3

select
F1=(select f1 from #temp1 where Flag=2)/(select f1 from #temp1 where Flag=1),
F2=(select f2 from #temp1 where Flag=2)/(select f2 from #temp1 where Flag=1),
F3=(select f3 from #temp1 where Flag=2)/(select f3 from #temp1 where Flag=1)
from #temp1 where Flag=3
/*
F1 F2 F3
--------------------------------------- --------------------------------------- ---------------------------------------
0.18000000000000000000 0.07500000000000000000 0.08000000000000000000

(1 行受影响)


*/

[thinclient]

update #temp1
set f1=sum(case when flag=2 then f1 else 0 end)/sum(case when flag=1 then f1 else 0 end),
f2=sum(case when flag=2 then f2 else 0 end)/sum(case when flag=1 then f2 else 0 end),
f3=sum(case when flag=2 then f3 else 0 end)/sum(case when flag=1 then f3 else 0 end)
where flag=1

[thinclient]

借了,1应改成3
update #temp1
set f1=sum(case when flag=2 then f1 else 0 end)/sum(case when flag=1 then f1 else 0 end),
f2=sum(case when flag=2 then f2 else 0 end)/sum(case when flag=1 then f2 else 0 end),
f3=sum(case when flag=2 then f3 else 0 end)/sum(case when flag=1 then f3 else 0 end)
where flag=3

[lxqlogo0]

感谢，结贴