/* 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') gocreate 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 iddrop 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') goselect id, [value] = stuff((select ',' + [value] from tb t where id = tb.id for xml path('')) , 1 , 1 , '') from tb group by iddrop 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_cursorselect * from @t drop table tb
--sql 2000用函数 create function dbo.f_str(@GROUPID int) returns varchar(1000) as begin declare @str varchar(1000) select @str = isnull(@str + ',' , '') + cast(value as varchar) from tb2 where GROUPID = @GROUPID return @str end go--调用函数 select tb1.id , value = dbo.f_str(tb1.GROUPID) from tb1,tb2 where tb1.GROUPID = tb2.GROUPID group by tb1.GROUPID--sql 2005 select tb1.GROUPID , t.value from tb1 , ( select GROUPID, [value] = stuff((select ',' + [value] from tb2 t where GROUPID = tb.GROUPID for xml path('')) , 1 , 1 , '') from tb2 group by GROUPID ) t where tb1.GROUPID = t.GROUPID
--构建模拟数据 if exists(select * from sysobjects where name='test1' and xtype='u') drop table test1Go create table Test1(id int, val int)Go insert into test1 select 1, 1 union all select 1, 2Go if exists(select * from sysobjects where name='test2' and xtype='u') drop table test2Go create table Test2(id int, val int)Go insert into test2 select 1, 1 union all select 1, 2 union all select 2, 1 union all select 2, 2 union all select 2, 3 union all select 2, 4Go --构造计算函数 GO if exists(select * from sysobjects where name='fn_test' and xtype='fn') drop function fn_test GOcreate function fn_test(@ID int) returns varchar(1000) as begin declare @s varchar(1000) set @s = ''
select @s = @s + cast(val as varchar(10))+ ', ' from test2 where id=@ID
return left(@s, len(@s)-1) endGo--查询示例 select Test1.id, dbo.fn_test(val) val from test1
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')
gocreate 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 iddrop 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')
goselect id, [value] = stuff((select ',' + [value] from tb t where id = tb.id for xml path('')) , 1 , 1 , '')
from tb
group by iddrop 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_cursorselect * from @t
drop table tb
3L使用是SQL 2000中的函数
http://topic.csdn.net/u/20080612/22/c850499f-bce3-4877-82d5-af2357857872.html
create function dbo.f_str(@GROUPID int) returns varchar(1000)
as
begin
declare @str varchar(1000)
select @str = isnull(@str + ',' , '') + cast(value as varchar) from tb2 where GROUPID = @GROUPID
return @str
end
go--调用函数
select tb1.id , value = dbo.f_str(tb1.GROUPID) from tb1,tb2 where tb1.GROUPID = tb2.GROUPID group by tb1.GROUPID--sql 2005
select tb1.GROUPID , t.value from tb1 ,
(
select GROUPID, [value] = stuff((select ',' + [value] from tb2 t where GROUPID = tb.GROUPID for xml path('')) , 1 , 1 , '')
from tb2
group by GROUPID
) t
where tb1.GROUPID = t.GROUPID
if exists(select * from sysobjects where name='test1' and xtype='u')
drop table test1Go
create table Test1(id int, val int)Go
insert into test1
select 1, 1
union all
select 1, 2Go
if exists(select * from sysobjects where name='test2' and xtype='u')
drop table test2Go
create table Test2(id int, val int)Go
insert into test2
select 1, 1
union all
select 1, 2
union all
select 2, 1
union all
select 2, 2
union all
select 2, 3
union all
select 2, 4Go --构造计算函数
GO
if exists(select * from sysobjects where name='fn_test' and xtype='fn')
drop function fn_test
GOcreate function fn_test(@ID int)
returns varchar(1000)
as
begin
declare @s varchar(1000)
set @s = ''
select @s = @s + cast(val as varchar(10))+ ', '
from test2
where id=@ID
return left(@s, len(@s)-1)
endGo--查询示例
select Test1.id, dbo.fn_test(val) val
from test1