问个sql循环问题

[kiruya0]

表A
master_id type desc
1 a1 cm
2 a2 mm
3 a1 m
4 a1 kg
5 a1 g
......

表B
item_id master_id value
1 1 30
1 3 40
1 5 10
2 2 12
2 3 44
3 4 12
5 2 67
.....

需要得出这样的结果

item_id value + desc
1 30cm,40m,10g,
2 44m
3 12kg
5

表A有5000+种 不要说用固定格式写....
表A只取type=a1的项目

哪位高手能解答下 谢谢

[中国风]

use Tempdb
go
--> --> 
 
if not object_id(N'Tempdb..#A') is null
	drop table #A
Go
Create table #A([master_id] int,[type] nvarchar(2),[desc] nvarchar(2))
Insert #A
select 1,N'a1',N'cm' union all
select 2,N'a2',N'mm' union all
select 3,N'a1',N'm' union all
select 4,N'a1',N'kg' union all
select 5,N'a1',N'g'
Go

 
if not object_id(N'Tempdb..#B') is null
	drop table #B
Go
Create table #B([item_id] int,[master_id] int,[value] int)
Insert #B
select 1,1,30 union all
select 1,3,40 union all
select 1,5,10 union all
select 2,2,12 union all
select 2,3,44 union all
select 3,4,12 union all
select 5,2,67
Go
WITH Cte
AS
(
Select 
	b.[item_id],
	RTRIM(b.[value])+[desc] AS [value + desc]
from #B AS b
	INNER JOIN #A AS c ON c.[master_id]=b.[master_id]
)
SELECT 
[item_id],
[value + desc]=STUFF((SELECT ','+[value + desc] FROM Cte WHERE item_id=a.[item_id] FOR XML PATH('')),1,1,'')
FROM Cte AS a
GROUP BY [item_id]
/*
item_id	value + desc
1	30cm,40m,10g
2	12mm,44m
3	12kg
5	67mm*/

[水族杰纶]

2005参考1喽
2000要用函数

[王向飞]

--> 数据库版本:
--> Microsoft SQL Server 2008 (RTM) - 10.0.1600.22
--> 测试数据：表A
IF  EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'表A') 
AND type in (N'U')) 
DROP TABLE 表A
GO

---->建表
create table 表A([master_id] int,[type] varchar(2),[desc] varchar(2))
insert 表A
select 1,'a1','cm' union all
select 2,'a2','mm' union all
select 3,'a1','m' union all
select 4,'a1','kg' union all
select 5,'a1','g'
GO

--> 数据库版本:
--> Microsoft SQL Server 2008 (RTM) - 10.0.1600.22
--> 测试数据：表B
IF  EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'表B') 
AND type in (N'U')) 
DROP TABLE 表B
GO

---->建表
create table 表B([item_id] int,[master_id] int,[value] int)
insert 表B
select 1,1,30 union all
select 1,3,40 union all
select 1,5,10 union all
select 2,2,12 union all
select 2,3,44 union all
select 3,4,12 union all
select 5,2,67
GO


;with TB
as
(SELECT b.item_id,rtrim(b.value)+a.[desc]  as [value+desc] FROM 表A  a join 表B b  on 
a.master_id=b.master_id
WHERE type='a1')

SELECT a.item_id,
[value+desc] =stuff((
select ','+convert(varchar(20),[value+desc]) FROM [TB] WHERE item_id = a.item_id  for xml path(''))
,1,1,'')
FROM [TB] a 
group by a.item_id

[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

[oO寒枫Oo]

--drop table TTB
--drop table TTA
--drop table #a
--drop table #b
--建表
Create table TTA
(
  master_id  int,
  mtype varchar(20),
  mdesc  varchar(10)
)
Create table TTB
(
  item_id  int,
  master_id  int,
  bvalue  int
)
insert into  TTA values(1,'a1','cm')
insert into  TTA values(2,'a2','mm')
insert into  TTA values(3,'a1','m')
insert into  TTA values(4,'a1','kg')
insert into  TTA values(5,'a1','g')

insert into  TTB values(1,1,30)
insert into  TTB values(1,3,40)
insert into  TTB values(1,5,10)
insert into  TTB values(2,2,12)
insert into  TTB values(2,3,44)
insert into  TTB values(3,4,12)
insert into  TTB values(5,2,67)

create table #a
(
  itemid  int ,
  newvalues varchar(50)
)
create table #b
(
  item_id  int ,
  new_values varchar(50)
)

----2初始结果
 insert into #a
 select item_id,cast(bvalue as varchar)+mdesc  as newvalues from TTB a left join 
   (
      select * from TTA where mtype='a1'
   ) b  
   on    a.master_id=b.master_id

select *  from #a


--3最终结果
declare @item_id int , @str varchar(1000)
declare my_cursor cursor for
select itemid  from #a
open my_cursor
fetch my_cursor into @item_id 
while @@FETCH_STATUS = 0
begin
  set @str=''
  SELECT @str = @str +cast(isnull(newvalues+',','') as varchar)+' '  from #a    where itemid=@item_id
  set @str=left(@str,len(@str)-1)
  insert into #b
  select @item_id,@str
  fetch my_cursor into @item_id
END
close my_cursor
deallocate my_cursor


select distinct *  from #b  

[randee_luo]

create table t1(master_id int identity(1,1),[type] varchar(3),[desc] varchar(10))

create table t2(item_id int,master_id int,[value] int)

insert t1([type],[desc]) select 'a1','cm' union all
select 'a2','mm' union all
select 'a1','m' union all
select 'a1','kg'union all
select 'a1','g'
select * from t1
insert t2 
select 1, 1, 30 union all
select 1, 3, 40 union all
select 1, 5, 10 union all
select 2, 2, 12 union all
select 2, 3, 44 union all
select 3, 4, 12 union all
select 5, 2, 67
select * from t2
;with cte as
(select a.item_id,case b.[type]when 'a2' then null else (convert(varchar(10),a.[value])+b.[desc]) end as [value+desc] from t2 a left join t1 b on a.master_id=b.master_id 
) 
select a.item_id,stuff((select ','+b.[value+desc] from cte b where a.item_id=b.item_id for xml path('') ),1,1,'') as [value+desc] from cte a group by a.item_id

item      [value+desc]
1	  30cm,40m,10g
2	  44m
3	  12kg
5	  NULL