一个SQL求和的问题

[c_cwh]

原始表
ID QTY
001 20
002 20
003 35
003 5
004 10
004 1

希望的结果
ID QTY 新列
001 20 20
002 20 20
003 35
003 5 40
004 10
004 1 11
请教高手，这个SQL语句怎么写？

[ForFumm]

没有规则？

[yibey]

create table #tb(num int identity(1,1)  ,ID varchar(20), QTY int)
insert into #tb
select 
'001', '20'
union
select
'002', '20'
union
select
'003', '35'
union
select
'003', '5'
union
select
'004', '10'
union
select
'004', '1'


select a.*,(case when a.num =(select max(num) from #tb where id = a.id) then b.xinlie else null end) as xinlie
 from #tb a left join 
(select id,sum(QTY)as xinlie from #tb group by id) b 
on a.id = b.id

[叶子]

declare @table table (ID varchar(3),QTY int)
insert into @table
select '001',20 union all
select '002',20 union all
select '003',35 union all
select '003',5 union all
select '004',10 union all
select '004',1

select t.*,新列=case when row_number() over (partition by t.ID order by t.ID )<>1 
and m.ID is not null then '' 
else cast((select sum(QTY) from @table where ID=t.ID) as varchar(10)) end
from @table t left join (select ID from @table group by ID having(count(*)>1)) m
on t.ID=m.ID order by m.ID,QTY

/*
ID   QTY         新列
---- ----------- ----------
001  20          20
002  20          20
003  5           
003  35          40
004  1           
004  10          11
*/