表里有2列(第一列是材料，第二列是用在什么项目上)，如：
comp project
fb A
fb B
fb C
fc B
fc D
fc E
fc F
要得到：
comp project
fb A,B,C
fc B,D,E,F
最好是函数，就是参数是fb, 函数返回A,B,C (逗号相隔)， 如果参数是fc, 将返回B,D,E,F
------解决思路----------------------
SELECT T.comp,STUFF((SELECT ','+project FROM TB WHERE T.comp=comp FOR XML PATH('')),1,1,'')project
FROM TB T
WHERE T.comp='fb'
GROUP BY comp------解决思路----------------------
select comp,project=stuff((select ','+project from TableA where comp=a.comp for xml path('')),1,1,'')
from TableA as a
group by comp------解决思路----------------------
参考
合并列值
--*******************************************************************************************
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。)
--=============================================================================
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
--1. 创建处理函数
CREATE FUNCTION dbo.f_strUnite(@id int)
RETURNS varchar(8000)
AS
BEGIN
DECLARE @str varchar(8000)
SET @str = ''
SELECT @str = @str + ',' + value FROM tb WHERE id=@id
RETURN STUFF(@str, 1, 1, '')
END
GO
-- 调用函数
SELECt id, value = dbo.f_strUnite(id) FROM tb GROUP BY id
drop table tb
drop function dbo.f_strUnite
go
/*
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
------解决思路----------------------
if object_id('F_Str') is not null
drop function F_Str
go
create function F_Str(@comp VARCHAR(50))
returns nvarchar(100)
as
begin
declare @S nvarchar(100)
select @S=isnull(@S+',','')+project from TableA where comp=@comp
return @S
end
GO
SELECT DISTINCT comp,dbo.F_Str(comp) FROM TableA------解决思路----------------------
DECLARE @comp VARCHAR(20)
SET @comp='fb'
;WITH cte(comp,project) AS(
SELECT 'fb', 'A' UNION ALL
SELECT 'fb', 'B' UNION ALL
SELECT 'fb', 'C' UNION ALL
SELECT 'fc', 'B' UNION ALL
SELECT 'fc', 'D' UNION ALL
SELECT 'fc', 'E' UNION ALL
SELECT 'fc', 'F'
)
SELECT comp
,STUFF((SELECT ','+project
FROM cte a
WHERE a.comp=b.comp
FOR XML PATH('')),1,1,'')
FROM cte b
WHERE b.comp=@comp
GROUP BY b.comp
------解决思路----------------------
SELECT comp,
project = Stuff((SELECT ','+project
FROM table1 AS b
WHERE b.comp = a.comp
for xml path('')),
1,1,'')
FROM (SELECT DISTINCT comp FROM table1) AS a
comp project
---- ------------
fb A,B,C
fc B,D,E,F