declare @mysc table
(
  id int,
  csa varchar(10),
  csb varchar(10)
);
insert into @mysc values(1,'abc','aac');
insert into @mysc values(2,'abc','aac');
insert into @mysc values(3,'abd','abb');
insert into @mysc values(4,'abd','abb');


;with c as
(
    select id,csa
    from @mysc
)
select  ROW_NUMBER() over(order by(c1.id)) as id, 
        cast(c1.id as varchar(10))+','+cast(c2.id as varchar(10)) as aid 
--INTO #lsttab  --将查询的结果插入临时表
from c c1
  join c c2 on c1.csa=c2.csa where c1.id<>c2.id and c2.id>c1.id

------解决方案--------------------
SQL code
;with f as
(
select
 row_number() over(order by(id)) as id, [aid]=stuff((select ','+[id] from tb  where csa=t.csa for xml path('')), 1, 1, '') 
from
 tb t
group by id
)

insert into mycs select * from f

------解决方案--------------------
SQL code

--> 测试数据: [mycs]
if object_id('[mycs]') is not null drop table [mycs]
create table [mycs] (id int,csa varchar(3),csb varchar(3))
insert into [mycs]
select 1,'abc','aac' union all
select 2,'abc','aab' union all
select 3,'abd','abb' union all
select 4,'abd','abb'

--开始查询
select id=identity(int,1,1),
aid=stuff((select ','+ltrim(id) from mycs where csa=a.csa for xml path('')),1,1,'')  
into #lstab
from mycs a 
group by csa

select * from #lstab

--结束查询
drop table [mycs],#lstab

/*
id          aid
----------- -------------------
1           1,2
2           3,4

(2 行受影响)

------解决方案--------------------
SQL code
/*
标题：按某字段合并字符串之一(简单合并)
作者：爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开)
时间：2008-11-06
地点：广东深圳

描述：将如下形式的数据按id字段合并value字段。
id    value
----- ------
1     aa
1     bb
2     aaa
2     bbb
2     ccc
需要得到结果：
id     value
------ -----------
1      aa,bb
2      aaa,bbb,ccc
即：group by id, 求 value 的和（字符串相加）
*/
--1、sql2000中只能用自定义的函数解决
create table tb(id int, value varchar(10))
insert into tb values(1, 'aa')
insert into tb values(1, 'bb')
insert into tb values(2, 'aaa')
insert into tb values(2, 'bbb')
insert into tb values(2, 'ccc')
go

create function dbo.f_str(@id varchar(10)) returns varchar(1000)
as
begin
  declare @str varchar(1000)
  select @str = isnull(@str + ',' , '') + cast(value as varchar) from tb where id = @id
  return @str
end
go

--调用函数
select id , value = dbo.f_str(id) from tb group by id

drop function dbo.f_str
drop table tb


--2、sql2005中的方法
create table tb(id int, value varchar(10))
insert into tb values(1, 'aa')
insert into tb values(1, 'bb')
insert into tb values(2, 'aaa')
insert into tb values(2, 'bbb')
insert into tb values(2, 'ccc')
go

select id, [value] = stuff((select ',' + [value] from tb t where id = tb.id for xml path('')) , 1 , 1 , '')
from tb
group by id

drop table tb


--3、使用游标合并数据
create table tb(id int, value varchar(10))
insert into tb values(1, 'aa')
insert into tb values(1, 'bb')
insert into tb values(2, 'aaa')
insert into tb values(2, 'bbb')
insert into tb values(2, 'ccc')
go
declare @t table(id int,value varchar(100))--定义结果集表变量
--定义游标并进行合并处理
declare my_cursor cursor local for
select id , value from tb
declare @id_old int , @id int , @value varchar(10) , @s varchar(100)
open my_cursor
fetch my_cursor into @id , @value
select @id_old = @id , @s=''
while @@FETCH_STATUS = 0
begin
    if @id = @id_old
       select @s = @s + ',' + cast(@value as varchar)
    else
      begin
        insert @t values(@id_old , stuff(@s,1,1,''))
        select @s