求sql写法，取得表格中，数据分组后，每组前3名的记录，不知该如何写？

[gos_q]

表格如下
ID Group Sales Amount
1 A Sales1 100
2 A Sales2 120
3 A Sales3 105
4 A Sales4 103
5 B Sales1 203
6 B Sales2 250
7 B Sales5 300
8 B Sales6 301
. . .
. . .
. . .

希望得到结果如下

Group Sales Amount
A Sales2 120
A Sales3 105
A Sales4 103
B Sales6 301
B Sales5 300
B Sales2 250

请问sql应该如何写？

[Garnett_KG]

select * from table a where id in (select top 3 id from table where id=a.id order by amount desc)

[ydage]

--假设上述表名为tb:
SELECT Group,Salces,Amount
FROM tb t
WHERE id IN(SELECT TOP 3 id FROM tb WHERE group = t.group ORDER BY Amount)

[utpcb]

select * from table a where id in (select top 3 id from table where id=a.id order by amount desc)

[nzperfect]

create table #T (ID int,[Group] varchar(2),Sales varchar(8),Amount int)
insert into #T
select 1,'A','Sales1',100 union all
select 2,'A','Sales2',120 union all
select 3,'A','Sales3',105 union all
select 4,'A','Sales4',103 union all
select 5,'B','Sales1',203 union all
select 6,'B','Sales2',250 union all
select 7,'B','Sales5',300 union all
select 8,'B','Sales6',301

select * from #T a where id in (select top 3 id from #T where [Group]=a.[Group] order by Amount desc)

/*
--------------------------
2	A	Sales2	120
3	A	Sales3	105
4	A	Sales4	103
6	B	Sales2	250
7	B	Sales5	300
8	B	Sales6	301
*/

[pt1314917]

select * from 表名 a where id in (select top 3 id from 表名 where Group=a.Group order by amount desc) 

[wgzaaa]

小小修正
select [Group],Sales,Amount from #t a
where id in(select top 3 id from #t b where a.[Group]=b.[Group] order by Amount desc)
order by [Group],Amount desc

[ydage]

[Quote=引用 2 楼 ydage 的回复:]
--假设上述表名为tb:
SELECT Group,Salces,Amount
FROM tb t
WHERE id IN(SELECT TOP 3 id FROM tb WHERE group = t.group ORDER BY Amount)
[/Quote]

忘记加降序排列了：
SELECT Group,Salces,Amount
FROM tb t
WHERE id IN(SELECT TOP 3 id FROM tb WHERE group = t.group ORDER BY Amount DESC)

[gos_q]

谢谢大家，现在结贴。