Oi pessoal, estou usando o seguinte código

ALTER PROCEDURE [dbo].[usp_get_all_groups] 
    -- Add the parameters for the stored procedure here
    @pStartIndex smallint,
    @pPageSize tinyint,
    @pOrderBy varchar
AS
BEGIN

 SELECT 
       *
       FROM
        (SELECT ROW_NUMBER() OVER (ORDER BY 

        CASE WHEN @pOrderBy='GroupId ASC' THEN UserGroups._id + ' ASC'
             WHEN @pOrderBy='GroupId DESC' THEN UserGroups._id + ' DESC'
             WHEN @pOrderBy='GroupCode ASC' THEN UserGroups.GroupCode + ' ASC'
             WHEN @pOrderBy='GroupCode DESC' THEN UserGroups.GroupCode + ' DESC'
        END        
        ) AS Row, * FROM UserGroups)
       AS StudentsWithRowNumbers
         WHERE Row>= @pStartIndex AND Row <= @pStartIndex + @pPageSize
END

Quando estou executando o processo armazenado usando o seguinte comando

DECLARE @return_value int

EXEC    @return_value = [dbo].[usp_get_all_groups]
        @pStartIndex = 0,
        @pPageSize = 15,
        @pOrderBy = N'GroupCode ASC'

SELECT  'Return Value' = @return_value

Estou obtendo esses resultados que não estão classificado

Row _id GroupCode   Description Type    IsActive
1   1   CS2009  CS 2009 Batch   S   1
2   2   IT2009  IT 2009 Batch   S   1
3   3   ME2009  ME 2009 Batch   S   1
4   4   EC2009  EC 2009 Batch   S   1
5   5   EE2009  EE 2009 Batch   S   1
6   8   CS_F    CS Faculties    F   1
7   9   IT_F    IT Faculties    F   1
8   10  ME_F    ME Faculties    F   1
9   11  EC_F    EC Faculties    F   1
10  12  EE_F    EE Faculties    F   1
11  13  BSC_F   Basic Science Faculties F   1
12  14  Accounts    Accounts    A   1
13  15  Mgmt    Management  M   1
14  16  Lib Library B   1
15  17  TnP Training & Placement    T   1

Pode me dizer o que mais é necessário?

Eu tentei isso, mas também está dando resultados não classificados de avião

SELECT 
        GroupTable._id,
        GroupTable.GroupCode,
        GroupTable.Type,
        GroupTable.Description
       FROM
        (SELECT ROW_NUMBER() OVER (ORDER BY 

        CASE WHEN @pOrderBy='GroupId ASC' THEN CONVERT(varchar(20), '_id ASC') 
             WHEN @pOrderBy='GroupId DESC' THEN CONVERT(varchar(20), '_id DESC') 
             WHEN @pOrderBy='GroupCode ASC' THEN CONVERT(varchar(20), @pOrderBy) 
             WHEN @pOrderBy='GroupCode DESC' THEN CONVERT(varchar(20), @pOrderBy) 
        END        
        ) AS Row, * FROM UserGroups)
       AS GroupTable
         WHERE Row>= @pStartIndex AND Row <= @pStartIndex + @pPageSize

       Select COUNT(*) as TotalRows from UserGroups where IsActive= 1