Paging And Sorting In Sql Server OR Getting Middle Rows In Sql Server

CREATE PROCEDURE Student_Paging
 @SortColumn varchar(50),
 @SortDirection varchar(4),
 @PageSize int,
 @PageNumber int
 
AS
BEGIN
 SELECT 
  ROW_NUMBER() OVER (ORDER BY (
          SELECT CASE @SortColumn
           WHEN 'Id'  THEN Id
           WHEN 'Name'  THEN Name 
           WHEN 'Marks' THEN Marks
          END
         )
       ) AS ROWNUMBER, 
  * 
 INTO 
  #Student_Page 
 FROM 
  student
  
 IF(@SortDirection = 'ASC')
 BEGIN
  SELECT  * 
  FROM  #Student_Page 
  WHERE  ROWNUMBER BETWEEN ((@PageNumber-1) * @PageSize) + 1  AND (@PageNumber * @PageSize)
  ORDER BY ROWNUMBER
 END
 ELSE IF(@SortDirection = 'DESC')
 BEGIN
  SELECT  * 
  FROM  #Student_Page 
  WHERE  ROWNUMBER BETWEEN ((@PageNumber-1) * @PageSize) + 1  AND (@PageNumber * @PageSize)
  ORDER BY ROWNUMBER DESC
 END
 
 
END
GO