SQL 简单问题

[ZhangNan20100811]

create table test
(
id int,
tName varchar(50)
)
drop table test
insert into test values(1,'ggg')
insert into test values(1,'ddd')
insert into test values(1,'hhh')
insert into test values(1,'yyy')
insert into test values(1,'uuu')

select * from test
-------------输出结果： ---
id tName
1 ggg
1 ddd
1 hhh
1 yyy
1 uuu


-------但我想要的结果是： ----
id tName
1 ggg,ddd,hhh,yyy,uuu


求查询语句 ？ 谢谢！

[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]

如果不分ID,仅对一个字段合并可如下:

/*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
*/

drop table tb

[中国风]

SELECT ID,
STUFF((SELECT ','+tName FROM test WHERE ID=a.ID FOR XML PATH('')),1,1,'') AS tName
FROM test AS a
GROUP BY ID

[ZhangNan20100811]

不改变表结构，也不用什么函数，只想要一条SQL语句能得出结果，拜托

[ZhangNan20100811]

[Quote=引用 3 楼 roy_88 的回复:]

SELECT ID,
STUFF((SELECT ','+tName FROM test WHERE ID=a.ID FOR XML PATH('')),1,1,'') AS tName
FROM test AS a
GROUP BY ID
[/Quote]

大哥，能给个不报错的吗？

[ZhangNan20100811]

[Quote=引用 3 楼 roy_88 的回复:]

SELECT ID,
STUFF((SELECT ','+tName FROM test WHERE ID=a.ID FOR XML PATH('')),1,1,'') AS tName
FROM test AS a
GROUP BY ID
[/Quote]
大哥，可以了。谢谢。。 你的SQL干净利落。。菜鸟很感谢！