question

[lin_now]

a 1001
a 1002
b 1001
b errs
-------
结果：
a 1001-1002
b 1001-errs

[黄_瓜]

--> 测试数据：[tb]
if object_id('[tb]') is not null drop table [tb]
go 
create table [tb]([id] varchar(1),[name] varchar(4))
insert [tb]
select 'a','1001' union all
select 'a','1002' union all
select 'b','1001' union all
select 'b','errs'
--------------开始查询--------------------------

select id, name =stuff((select '-'+name from tb where id=a.id for xml path('')),1,1,'')
from [tb] a
group by id
----------------结果----------------------------
/* 
id   name
---- -------------
a    1001-1002
b    1001-errs
*/

[黄_瓜]

/****************************************************************************************************************************************************** 
合并分拆表数据 

整理人：中国风(Roy) 

日期:2008.06.06 
******************************************************************************************************************************************************/ 

--> --> (Roy)生成測試數據 

if not object_id('Tab') is null 
    drop table Tab 
Go 
Create table Tab([Col1] int,[Col2] nvarchar(1)) 
Insert Tab 
select 1,N'a' union all 
select 1,N'b' union all 
select 1,N'c' union all 
select 2,N'd' union all 
select 2,N'e' union all 
select 3,N'f' 
Go 

合并表: 

SQL2000用函数: 

go 
if object_id('F_Str') is not null 
    drop function F_Str 
go 
create function F_Str(@Col1 int) 
returns nvarchar(100) 
as 
begin 
    declare @S nvarchar(100) 
    select @S=isnull(@S+',','')+Col2 from Tab where Col1=@Col1 
    return @S 
end 
go 
Select distinct Col1,Col2=dbo.F_Str(Col1) from Tab 

go 

SQL2005用XML: 

方法1: 

select 
    a.Col1,Col2=stuff(b.Col2.value('/R[1]','nvarchar(max)'),1,1,'') 
from 
    (select distinct COl1 from Tab) a 
Cross apply 
    (select COl2=(select N','+Col2 from Tab where Col1=a.COl1 For XML PATH(''), ROOT('R'), TYPE))b 

方法2: 

select 
    a.Col1,COl2=replace(b.Col2.value('/Tab[1]','nvarchar(max)'),char(44)+char(32),char(44)) 
from 
    (select distinct COl1 from Tab) a 
cross apply 
    (select Col2=(select COl2 from Tab  where COl1=a.COl1 FOR XML AUTO, TYPE) 
                .query(' <Tab> 
                {for $i in /Tab[position() <last()]/@COl2 return concat(string($i),",")} 
                {concat("",string(/Tab[last()]/@COl2))} 
                </Tab>') 
                )b 

SQL05用CTE: 

;with roy as(select Col1,Col2,row=row_number()over(partition by COl1 order by COl1) from Tab) 
,Roy2 as 
(select COl1,cast(COl2 as nvarchar(100))COl2,row from Roy where row=1 
union all 
select a.Col1,cast(b.COl2+','+a.COl2 as nvarchar(100)),a.row from Roy a join Roy2 b on a.COl1=b.COl1 and a.row=b.row+1) 
select Col1,Col2 from Roy2 a where row=(select max(row) from roy where Col1=a.COl1) order by Col1 option (MAXRECURSION 0) 


生成结果: 
/* 
Col1        COl2 
----------- ------------ 
1          a,b,c 
2          d,e 
3          f 

(3 行受影响) 
*/ 


--参考
拆分表:

--> --> (Roy)生成測試數據
 
if not object_id('Tab') is null
    drop table Tab
Go
Create table Tab([Col1] int,[COl2] nvarchar(5))
Insert Tab
select 1,N'a,b,c' union all
select 2,N'd,e' union all
select 3,N'f'
Go

--SQL2000用辅助表:
if object_id('Tempdb..#Num') is not null
    drop table #Num
go
select top 100 ID=Identity(int,1,1) into #Num from syscolumns a,syscolumns b
Select 
    a.Col1,COl2=substring(a.Col2,b.ID,charindex(',',a.Col2+',',b.ID)-b.ID) 
from 
    Tab a,#Num b
where
    charindex(',',','+a.Col2,b.ID)=b.ID --也可用 substring(','+a.COl2,b.ID,1)=','
--2000不使用辅助表
Select
    a.Col1,COl2=substring(a.Col2,b.number,charindex(',',a.Col2+',',b.number)-b.number) 
from 
    Tab a join master..spt_values  b 
    ON B.type='p' AND B.number BETWEEN 1 AND LEN(A.col2)
where
     substring(','+a.COl2,b.number,1)=','


SQL2005用Xml:

select 
    a.COl1,b.Col2
from 
    (select Col1,COl2=convert(xml,'<root><v>'+replace(COl2,',','</v><v>')+'</v></root>') from Tab)a
outer apply
    (select Col2=C.v.value('.','nvarchar(100)') from a.COl2.nodes('/root/v')C(v))b




SQL05用CTE:

;with roy as 
(select Col1,COl2=cast(left(Col2,charindex(',',Col2+',')-1) as nvarchar(100)),Split=cast(stuff(COl2+',',1,charindex(',',Col2+','),'') as nvarchar(100)) from Tab
union all
select Col1,COl2=cast(left(Split,charindex(',',Split)-1) as nvarchar(100)),Split= cast(stuff(Split,1,charindex(',',Split),'') as nvarchar(100)) from Roy where split>''
)
select COl1,COl2 from roy order by COl1 option (MAXRECURSION 0)

生成结果:
/*
Col1        COl2
----------- -----
1           a
1           b
1           c
2           d
2           e
3           f
*/

[dawugui]

/*
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 = ',' + cast(@value as varchar) , @id_old = @id
      end
    fetch my_cursor into @id , @value
END
insert @t values(@id_old , stuff(@s,1,1,''))
close my_cursor
deallocate my_cursor

select * from @t
drop table tb

[dawugui]

--如果每组都是两个值,可直接使用分组来做.

create table tb(c1 varchar(10), c2 varchar(10))
insert into tb values('a', '1001')
insert into tb values('a', '1002')
insert into tb values('b', '1001')
insert into tb values('b', 'errs')
go

select c1 , c2 = (min(c2) + '-' + max(c2)) from tb group by c1

drop table tb

/*
c1         c2                    
---------- --------------------- 
a          1001-1002
b          1001-errs

（所影响的行数为 2 行）
*/

--如果每组数量不确定,sql 2000需要使用函数来做.

create table tb(c1 varchar(10), c2 varchar(10))
insert into tb values('a', '1001')
insert into tb values('a', '1002')
insert into tb values('b', '1001')
insert into tb values('b', 'errs')
go

create function dbo.f_str(@c1 varchar(10)) returns varchar(1000)
as
begin
  declare @str varchar(1000)
  select @str = isnull(@str + '-' , '') + cast(c2 as varchar) from tb where c1 = @c1
  return @str
end
go

--调用函数
select c1 , c2 = dbo.f_str(c1) from tb group by c1

drop function dbo.f_str
drop table tb

/*
c1         c2       
---------- ---------
a          1001-1002
b          1001-errs

（所影响的行数为 2 行）
*/

--sql 2005如下:

create table tb(c1 varchar(10), c2 varchar(10))
insert into tb values('a', '1001')
insert into tb values('a', '1002')
insert into tb values('b', '1001')
insert into tb values('b', 'errs')
go

select c1, c2 = stuff((select '-' + c2 from tb t where c1 = tb.c1 for xml path('')) , 1 , 1 , '')
from tb
group by c1

drop table tb

/*
c1         c2
---------- ----------
a          1001-1002
b          1001-errs

(2 行受影响)

*/

[开着拖拉机泡妞]

[Quote=引用 1 楼 beirut 的回复:]

SQL code
--> 测试数据：[tb]
if object_id('[tb]') is not null drop table [tb]
go
create table [tb]([id] varchar(1),[name] varchar(4))
insert [tb]
select 'a','1001' union all
select 'a','1002' union all
s……
[/Quote]

顶一个，我就不来贴了