有如下一个表:
tableA
id riqi
0003 20090201
0003 20090202
0004 20090202
0004 20090204
如何转换成:
id riqi
0003 20090201 20090202
0004 20090202 20090204或者
riqi id
20090201 0003
20090202 0003 0004
20090204 0004
tableA
id riqi
0003 20090201
0003 20090202
0004 20090202
0004 20090204
如何转换成:
id riqi
0003 20090201 20090202
0004 20090202 20090204或者
riqi id
20090201 0003
20090202 0003 0004
20090204 0004
goinsert into tableA
select '0003','20090201' union all
select '0003','20090202' union all
select '0004','20090202' union all
select '0004','20090204'
go
drop function dbo.getstr
create function dbo.getstr(@id nvarchar(20))
returns nvarchar(200)
as
begin
declare @str as nvarchar(200)
select @str=isnull(@str,'')+riqi+' ' from tableA where id=@id
return @str
end
go
select distinct id,dbo.getstr(id) as riqi from tableA
--
id riqi
-------------------- -------------------
0003 20090201 20090202
0004 20090202 20090204
'CREATE FUNCTION' 必须是查询批次中的第一个语句。
消息 137,级别 15,状态 2,第 8 行
必须声明标量变量 "@id"。
消息 178,级别 15,状态 1,第 9 行
在此上下文中不能使用带有返回值的 RETURN 语句。
消息 4121,级别 16,状态 1,第 1 行
找不到列 "dbo" 或用户定义的函数或聚合 "dbo.getstr",或者名称不明确。
drop table tableA
go
create table tableA(id nvarchar(20),riqi nvarchar(20))
goinsert into tableA
select '0003','20090201' union all
select '0003','20090202' union all
select '0004','20090202' union all
select '0004','20090204'
goif object_id('dbo.getstr') is not null
drop function dbo.getstr
go
create function dbo.getstr(@id nvarchar(20))
returns nvarchar(200)
as
begin
declare @str as nvarchar(200)
select @str=isnull(@str,'')+riqi+' ' from tableA where id=@id
return @str
end
go
select distinct id,dbo.getstr(id) as riqi from tableA
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 int) returns varchar(100)
as
begin
declare @str varchar(1000)
set @str = ''
select @str = @str + ',' + cast(value as varchar) from tb where id = @id
set @str = right(@str , len(@str) - 1)
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
go
create table [tableA]([id] varchar(4),[riqi] varchar(10))
insert [tableA]
select '0003','20090201' union all
select '0003','20090202' union all
select '0004','20090202' union all
select '0004','20090204'select
riqi,
stuff((select ' '+id from tableA where riqi=t.riqi for xml path('')),1,1,'') as id
from
tableA t
group by
riqi--测试结果:
/*
riqi id
---------- --------------------------------------
20090201 0003
20090202 0003 0004
20090204 0004(3 行受影响)
*/