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
---------------------------------------------------- /*如何将一列中所有的值一行显示 数据源 a b c d e 结果 a,b,c,d,e */create table tb(col varchar(20)) insert tb values ('a') insert tb values ('b') insert tb values ('c') insert tb values ('d') insert tb values ('e') go--方法一 declare @sql varchar(1000) set @sql = '' select @sql = @sql + t.col + ',' from (select col from tb) as t set @sql='select result = ''' + left(@sql , len(@sql) - 1) + '''' exec(@sql) /* result ---------- a,b,c,d,e, */--方法二 declare @output varchar(8000) select @output = coalesce(@output + ',' , '') + col from tb print @output /* a,b,c,d,e */---方法三 declare @s varchar(1000) select @s=isnull(@s+',' , '')+col from tb select @s /* a,b,c,d,e */drop table tb -------------
很好啊!!!太强大了!!!多谢了fredrickhu。 还有一个问题,如果是一列中有数值是重复的,我只想显示其一怎么办 数据源 A B C A B C 结果 A,B,C 这个怎样解决??
--先构建个临时表 ;with cte as( select distinct col from tb ) --再合并列值
use Tempdb go --> -->
if not object_id(N'Tempdb..#T') is null drop table #T Go Create table #T([列1] nvarchar(1),[列2] nvarchar(1)) Insert #T select N'A',N'O' union all select N'B',N'P' union all select N'C',N'Q' union all select N'D',N'R' union all select N'E',N'S' Go DECLARE @s1 NVARCHAR(max),@s2 NVARCHAR(max)SELECT @s1=ISNULL(@s1+',','')+[列1] FROM #T GROUP BY [列1] SELECT @s2=ISNULL(@s2+',','')+[列2] FROM #T GROUP BY [列2]SELECT @s1 SELECT @s2
--*******************************************************************************************
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
/*如何将一列中所有的值一行显示
数据源
a
b
c
d
e
结果
a,b,c,d,e
*/create table tb(col varchar(20))
insert tb values ('a')
insert tb values ('b')
insert tb values ('c')
insert tb values ('d')
insert tb values ('e')
go--方法一
declare @sql varchar(1000)
set @sql = ''
select @sql = @sql + t.col + ',' from (select col from tb) as t
set @sql='select result = ''' + left(@sql , len(@sql) - 1) + ''''
exec(@sql)
/*
result
----------
a,b,c,d,e,
*/--方法二
declare @output varchar(8000)
select @output = coalesce(@output + ',' , '') + col from tb
print @output
/*
a,b,c,d,e
*/---方法三
declare @s varchar(1000)
select @s=isnull(@s+',' , '')+col from tb
select @s
/*
a,b,c,d,e
*/drop table tb
-------------
还有一个问题,如果是一列中有数值是重复的,我只想显示其一怎么办
数据源
A
B
C
A
B
C
结果
A,B,C
这个怎样解决??
--先构建个临时表
;with cte as(
select distinct col from tb
)
--再合并列值
go
--> -->
if not object_id(N'Tempdb..#T') is null
drop table #T
Go
Create table #T([列1] nvarchar(1),[列2] nvarchar(1))
Insert #T
select N'A',N'O' union all
select N'B',N'P' union all
select N'C',N'Q' union all
select N'D',N'R' union all
select N'E',N'S'
Go
DECLARE @s1 NVARCHAR(max),@s2 NVARCHAR(max)SELECT @s1=ISNULL(@s1+',','')+[列1] FROM #T GROUP BY [列1]
SELECT @s2=ISNULL(@s2+',','')+[列2] FROM #T GROUP BY [列2]SELECT @s1
SELECT @s2