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- /*
- 標題:按某字段合併字符串之一(簡單合併)
- 作者:愛新覺羅.毓華(十八年風雨,守得冰山雪蓮花開)
- 時間:2008-11-06
- 地點:廣東深圳
- 描述:將如下形式的數據按id字段合併value字段。
- id value
- ----- ------
- 1 aa
- 1 bb
- 2 aaa
- 2 bbb
- 2 ccc
- 需要得到結果:
- id value
- ------ -----------
- 1 aa,bb
- 2 aaa,bbb,ccc
- 即:group by id, 求 value 的和(字符串相加)
- */
- --1、sql2000中只能用自定義的函數解決
- 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 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
- --調用函數
- 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、使用游標合併數據
- 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))--定義結果集表變量
- --定義游標並進行合併處理
- 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
複製代碼 Reference: http://topic.csdn.net/u/20100511 ... e-01a471fc5841.html |
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