帮忙看看有什么问题,急啊...

[it_sql]

table1
a,b
1,dh10001005
1,dh10001006
1,dh10001007
1,dh10001008
1,dh10001009
1,dh10001010
2,dh10001005
2,dh10001006
2,dh10001007
2,dh10001008
2,dh10001009
2,dh10001010
.....
我想得到的结果是:
1,dh10001005/dh10001006/dh10001007/dh10001008/dh10001009...
2,dh10001005/dh10001006/dh10001007/dh10001008/dh10001009...
我的函数是:

SQL codeCREATE function dbo.hebing(@a VARCHAR(20))
returns varchar(8000)
as
begin
declare @ret varchar(8000)
set @ret = ''
select @ret = @ret+case when charindex(b+'/',@ret) > 0 then '' else '/'+rtrim(b) end from table where a= @a
set @ret = stuff(@ret,1,1,'')
return @ret
end
select a,dbo.hebing(a) from table

假如1有200多行,用dbo.hebing(a)查询到的结果是不全的,少了很多,我用len()返回了看一看没有到8000个字符啊,是为什么呢?

[wzy_love_sly]

CREATE  function  dbo.hebing(@a VARCHAR(20))
returns  varchar(8000)
as
begin
        declare  @ret  varchar(8000)
        select  @ret  =  isnull(@ret+',','')+ b   from  tb where  a=  @a
      set  @ret  =  stuff(@ret,1,1,'')
        return  @ret 
end

[中国风]

SQL05用nvarchar(max)

--合并分拆表
/******************************************************************************************************************************************************
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)
*/


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)=','


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
*/

[wzy_love_sly]

select a,dbo.hebing(a) from tb  group by a

[中国风]

假如1有200多行,用dbo.hebing(a)查询到的结果是不全的,少了很多,我用len()返回了看一看没有到8000个字符啊,是为什么呢?

不可用len统计,改为DATALENGTH统计

如:中文占两个字节,数字、字符占一个...

[中国风]

如:全角(占两个字节)与半角(占1个字节)等等都不相同

[水族杰纶]

/*有一種可能就是你查詢分析器默認每行最大顯示256
你到工具--選項--結果--每個資料行最多字元數改為8000看看(我繁體系統表達可能有點出入)
*/

[rucypli]

[Quote=引用 4 楼 roy_88 的回复:]
HTML code假如1有200多行,用dbo.hebing(a)查询到的结果是不全的,少了很多,我用len()返回了看一看没有到8000个字符啊,是为什么呢?



不可用len统计,改为DATALENGTH统计

如:中文占两个字节,数字、字符占一个...
[/Quote]
估计是这个原因