自动按字符串长度拆分-----高人们救救“火”啊~~~~~~~~~
create   table   bb   (studentid     varchar(100),markstr   varchar(50))
insert   into   bb   select  
'2002081108 ', 'AAAAAAAAAAAAAAAAAAAAAAAAA '   union   all   select
'2002081107 ', 'BBBBBBBBBBBBBBBBBBBBBBBBB '   union   all   select
'2002081109 ', 'CCCCCCCCCCCCCCCCCCCCCCCCC '   union   all   select
'2002081110 ', 'DDDDDDDDDDDDDDDDDDCDCDDCC '   union   all   select
'2002081111 ', 'DDDEEDDDDDDDDDDEDDCDCDDCC '

如上建立数据表，想要把markstr拆分开来，得到如下的结果，并把结果集生成一张表，如下，如何写存储过程?
studentid no1 no2 no3 no4 no5 no6 no7 no8 no9 no10 no11 no12 no13 no14 no15 no16 no17 no18 no19 no20 no21 no22 no23 no24 no25
2002081108 A A A A A A A A A A A A A A A A A A A A A A A A A
2002081107 B B B B B B B B B B B B B B B B B B B B B B B B B
2002081109 C C C C C C C C C C C C C C C C C C C C C C C C C
2002081110 D D D D D D D D D D D D D D D D D D C D C D D C C
2002081111 D D D E E D D D D D D D D D D E D D C D C D D C C
想要除
select   studentid,substring(markstr,1,1)   as   no1,substring(markstr,2,1)   as   no2,substring(markstr,3,1)   as   no3,
substring(markstr,4,1)   as   no4,substring(markstr,5,1)   as   no5,substring(markstr,6,1)   as   no6,substring(markstr,7,1)   as   no7,
substring(markstr,8,1)   as   no8,substring(markstr,9,1)   as   no9,substring(markstr,10,1)   as   no10,substring(markstr,11,1)   as   no11,
substring(markstr,12,1)   as   no12,substring(markstr,13,1)   as   no13,substring(markstr,14,1)   as   no14,substring(markstr,15,1)   as   no15,
substring(markstr,16,1)   as   no16,substring(markstr,17,1)   as   no17,substring(markstr,18,1)   as   no18,substring(markstr,19,1)   as   no19,
substring(markstr,20,1)   as   no20,substring(markstr,21,1)   as   no21,substring(markstr,22,1)   as   no22,substring(markstr,23,1)   as   no23,
substring(markstr,24,1)   as   no24,substring(markstr,25,1)   as   no25     into   aa   from   bb
类似的以外的答案~~~~~~~~~~~~~~~~~~~~~~这个方法太麻烦，而且，总项数是写死了的，如果增加26项，就要改，所以希望存储过程能按markstr的长度自动拆分，拜托各位了，帮帮忙*_*



------解决方案--------------------
declare @i int
declare @t int
declare @sql varchar(8000)
set @sql= ' '
set @t=1
select @i=max(len(markstr)) from bb
while(@t <=@i)
begin
set @sql=@sql+ ',substring(markstr, '+cast(@t as varchar)+ ',1) as no '+cast(@t as varchar)
set @t=@t+1
end
set @sql= 'select studentid, '+stuff(@sql,1,1, ' ')+ ' into aa from bb '
exec(@sql)