急~！求一句sql语句！在线等~！谢谢！！！！！！！！
有两个表a、b
  a表字段（a1，a2，a3）均为varchar(22)
  b表字段（b1   int,b2   varchar(22)）
  问题：
          把b表中的数据根据b1进行排序，取前三条数据插入表a
  如：
  表b   b1       b2
        ----     -----
        34         b
        78         bb
        98         bbb
根据降序排序后写入表a
  a1     a2     a3  
  ---   ---   ---
  bbb   bb     b

谢谢~！

------解决方案--------------------
create table a(
a1 varchar(22),a2 varchar(22),a3 varchar(22)
)
create table b(
b1 int,
b2 varchar(22)
)

insert into b
select 34, 'b ' union all
select 78, 'bb ' union all
select 98, 'bbb '

declare @b varchar(100),@s varchar(200)
set @b= ' '
select top 3 @b=@b+ ', ' ' '+b2+ ' ' ' ' from b order by b1
set @b=stuff(@b,1,1, ' ')
set @s= 'insert into a select '+@b
exec(@s)

select * from a

drop table a
drop table b
------解决方案--------------------
Create Table a(a1 varchar(22), a2 varchar(22),a3 varchar(22))
Create Table b(b1 int, b2 varchar(22))

Insert b Select 34, 'b '
Union All Select 78, 'bb '
Union All Select 98, 'bbb '
GO
Insert a
Select TOP 1 b2,
(Select TOP 1 b2 From b Where b1 < T.b1 Order By b1 Desc),
(Select TOP 1 b2 From b Where b1 Not In (Select TOP 2 b1 From b Order By b1 Desc) Order By b1 Desc) From b T Order By b1 Desc

Select * From a
GO
Drop Table a, b
--Result
/*
a1 a2 a3
bbb bb b
*/
------解决方案--------------------
create table a(a1 varchar(22),a2 varchar(22),a3 varchar(22))
create table b(b1 int,b2 varchar(22))
insert into b select 34, 'b '
insert into b select 78, 'bb '
insert into b select 98, 'bbb '

insert into a
Select TOP 1 b2 as a1,
(Select TOP 1 b2 From b Where b1 < T.b1 Order By b1 Desc) as a2,
(Select TOP 1 b2 From b Where b1 <T.b1 order by b1) as a3
From b T Order By b1 Desc

select * from a
drop table a,b
a1 a2 a3
---------------------- ---------------------- ----------------------
bbb bb b

(1 行受影响)