CREATE FUNCTION F_Covert( 
@str nvarchar(4000) 
) returns nvarchar(4000) 
as 
 
begin 
   declare @endp int,@endflag int,@length int,@i int 
   ,@reversestr nvarchar(4000),@return_str nvarchar(4000) 
   select @endflag = 0,@length=len(@str),@i=1,@reversestr = reverse(@str),@endp = 0 
   while (@endflag = 0 and @i<=@length) 
   begin 
      if(SUBSTRING(@reversestr,@i,1) != ‘? ‘) 
        begin 
          set @endflag = 1 
          set @endp = @length - @i + 1 
        end 
        set @i = @i + 1 
   end 
   set @return_str = substring(@str,1,@endp) 
   return @return_str 
end 
 
原文:http://www.cnblogs.com/JoePotter/p/4992188.html