標(biāo)題：按某字段合并字符串之一(簡單合并)
描述：將如下形式的數(shù)據(jù)按id字段合并value字段。
id value
----- ------
1 aa
1 bb
2 aaa
2 bbb
2 ccc
需要得到結(jié)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(shù)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(diào)用函數(shù)
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(biāo)合并數(shù)據(jù)
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(jié)果集表變量
--定義游標(biāo)并進(jìn)行合并處理
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
以上就是關(guān)于分組字符合并SQL語句的介紹。希望對(duì)大家有所幫助。
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