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  • 数据库合并数据sql

    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 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 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
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  • 原文地址:https://www.cnblogs.com/shuilangyizu/p/5951978.html
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