表结构 产品 原料 比率
101 a 30
101 b 70
102 a 20
102 c 30
102 d 50
变为以下形式产品 原料比例
101 a30%b70%
102 a20%c30%d50%在线等,急!!!
101 a 30
101 b 70
102 a 20
102 c 30
102 d 50
变为以下形式产品 原料比例
101 a30%b70%
102 a20%c30%d50%在线等,急!!!
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')
goCREATE 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 iddrop 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 tbdrop 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')
goselect 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
无论是在sql 2000,还是在 sql 2005 中,都没有提供字符串的聚合函数,
所以,当我们在处理下列要求时,会比较麻烦:
有表tb, 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-- 1. 创建处理函数
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, values=dbo.f_str(id)
FROM tb
GROUP BY id-- 2. 新的解决方法
-- 示例数据
DECLARE @t TABLE(id int, value varchar(10))
INSERT @t SELECT 1, 'aa'
UNION ALL SELECT 1, 'bb'
UNION ALL SELECT 2, 'aaa'
UNION ALL SELECT 2, 'bbb'
UNION ALL SELECT 2, 'ccc'-- 查询处理
SELECT *
FROM(
SELECT DISTINCT
id
FROM @t
)A
OUTER APPLY(
SELECT
[values]= STUFF(REPLACE(REPLACE(
(
SELECT value FROM @t N
WHERE id = A.id
FOR XML AUTO
), '<N value="', ','), '"/>', ''), 1, 1, '')
)N/*--结果
id values
----------- ----------------
1 aa,bb
2 aaa,bbb,ccc
(2 行受影响)
--*/CSDN 社区帖子地址 附: 合并与分拆的CLR, sql2005的示例中有:
在安装sql 2005的示例后,默认安装目录为
drive:\Program Files\Microsoft SQL Server\90\Samples\Engine\Programmability\CLR\StringUtilities中
OUTER APPLY(SELECT
[比率]= STUFF(REPLACE(REPLACE((
SELECT [比率] FROM @t N WHERE [产品] = A.[产品]
FOR XML AUTO),'<N 比率="','%'),'"/>', ''), 1, 1, ''))N
create table s(产品 int,原料 varchar(1),比率 int)
insert into s
select 101,'a',30 union all
select 101,'b',70 union all
select 102,'a',20 union all
select 102,'c',30 union all
select 102,'d',50
create function f_s(@产品 int)
returns varchar(500)
as
begin
declare @sql varchar(500)
set @sql=''
select @sql=@sql+原料+ltrim(cast(比率*100.0/(select sum(比率) from s where 产品=@产品) as numeric(5,2)))+'%'
from
(select 产品,原料,比率=sum(比率) from s where 产品=@产品 group by 产品,原料)a
return @sql
end
select distinct 产品,原料比例=dbo.f_s(产品) from s
05以上就方便了APPLY
drop table tb
go
create table tb(产品 varchar(10),原料 varchar(10),比率 int)
go
insert into tb
select '101','a',30 union all
select '101','b',70 union all
select '102','a',20 union all
select '102','c',30 union all
select '102','d',50
go
if object_id('uf_tb') is not null
drop function uf_tb
go
create function uf_tb(@product varchar(10))
returns varchar(8000)
as
begin
declare @s varchar(8000)
set @s=''
select @s=@s+原料+cast(比率 as varchar(10))+'%' from tb where 产品=@product
return @s
end
goselect distinct 产品,原料比例=dbo.uf_tb(产品) from tb