标题:按某字段合并字符串之一(简单合并)

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 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 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

以上就是关于分组字符合并SQL语句的介绍。希望对大家有所帮助。

发表评论

您的电子邮箱地址不会被公开。 必填项已用*标注