***********************请教一个sql查询的问题**************************
表a
id   amount  
1       3
2       15
3       20
4       28

给一个数字@b   =   30
要查出b在对amount求和的哪条记录的范围内

比如   1   +   15   +   20   >   30并且   1   +   15   <   30
那么@b就应该在3这个id范围内

不知道我说清楚意思没有

谢谢各位




------解决方案--------------------
declare @t table(id int,amount int)
insert into @t select 1,3
insert into @t select 2,15
insert into @t select 3,20
insert into @t select 4,28

declare @a int,@b int,@id int
set @a=0
set @b=30

select
@id=case
when @b> @a and @b <=@a+amount then id
else @id
end,
@a =@a+amount
from
@t

select @id as id

/*
id
-----------
3
*/
------解决方案--------------------
declare @t table(id int,amount int)
insert into @t select 1,3
insert into @t select 2,15
insert into @t select 3,20
insert into @t select 4,28

select a.id from @t a
where (select sum(amount) from @t where id <a.id) <30 and (select sum(amount) from @t where id <=a.id)> =30