合并列值
原著：邹建
改编：爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开) 2007-12-16 广东深圳

表结构，数据如下：
id value
----- ------
1 aa
1 bb
2 aaa
2 bbb
2 ccc

需要得到结果：
id values
------ -----------
1 aa,bb
2 aaa,bbb,ccc
即：group by id, 求 value 的和（字符串相加）

1. 旧的解决方法(在sql server 2000中只能用函数解决。)
--1. 创建处理函数
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 int)
RETURNS varchar(8000)
AS
BEGIN
  DECLARE @r varchar(8000)
  SET @r = ''
  SELECT @r = @r + ',' + value FROM tb WHERE id=@id
  RETURN STUFF(@r, 1, 1, '')
END
GO

-- 调用函数
SELECt id, value = dbo.f_str(id) FROM tb GROUP BY id

drop table tb
drop function dbo.f_str

/*
id value   
----------- -----------
1 aa,bb
2 aaa,bbb,ccc
（所影响的行数为 2 行）
*/

--2、另外一种函数.
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

--创建一个合并的函数
create function f_hb(@id int)
returns varchar(8000)
as
begin
  declare @str varchar(8000)
  set @str = ''
  select @str = @str + ',' + cast(value as varchar) from tb where id = @id
  set @str = right(@str , len(@str) - 1)
  return(@str)
End
go

--调用自定义函数得到结果：
select distinct id ,dbo.f_hb(id) as value from tb

drop table tb
drop function dbo.f_hb

/*
id value   
----------- -----------
1 aa,bb
2 aaa,bbb,ccc
（所影响的行数为 2 行）
*/

2. 新的解决方法(在sql server 2005中用OUTER APPLY等解决。)
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
-- 查询处理
SELECT * FROM(SELECT DISTINCT id FROM tb)A OUTER APPLY(
  SELECT [values]= STUFF(REPLACE(REPLACE(
  (
  SELECT value FROM tb N
  WHERE id = A.id
  FOR XML AUTO
  ), '<N value="', ','), '"/>', ''), 1, 1, '')
)N
drop table tb

/*
id values
----------- -----------
1 aa,bb
2 aaa,bbb,ccc

(2 行受影响)
*/

--SQL2005中的方法2
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, [values]=stuff((select ','+[value] from tb t where id=tb.id for xml path('')), 1, 1, '')
from tb
group by id

/*
id values
----------- --------------------
1 aa,bb
2 aaa,bbb,ccc

(2 row(s) affected)

*/

drop table tb

------解决方案--------------------
没什么规律，不好合并。

------解决方案--------------------

SQL code

create table #test
(
id int,
val nvarchar(20)
)
insert into #test values(1,'门')
insert into #test values(1,'men')
insert into #test values(2,'们')
insert into #test values(2,'men')
insert into #test values(3,'大')
insert into #test values(3,'da')
insert into #test values(4,'打')
insert into #test values(4,'da')

with t as
(
select  min(a.val) as pinyin , max(a.val) as wenzi 
from #test a,#test b  where a.val=b.val group by a.id 
)
select pinyin,( select wenzi+' ' from t a
where a.pinyin=b.pinyin
 for xml path('') ) as wenzi
 from t b group by pinyin

------解决方案--------------------
1、
先使用http://www.cnblogs.com/ret00100/archive/2010/08/06/1793725.html 下面的第二个函数求出每个汉字的拼音，然后再合并字符串（2楼的方法）
2、如果是按照6楼的格式的话，即第一行是汉字，下面一行是该汉字的拼音，那么按照6楼的即可