SELECT  A + B + C AS total
        
FROM    ( SELECT DISTINCT
                    MAX( CASE WHEN CRS.CN IN ( 'G21021', 'G21022', 'G21031',
                                            'G21032', 'G21000', 'G21011',
                                            'G21012' )
                                AND TST.PT = 1
                                AND TST.RS < 3 THEN 1
                           ELSE 0
                      END ) AS A,
                  MAX  ( CASE WHEN CRS.CN IN ( 'G22021', 'G22022', 'G22031',
                                            'G22032', 'G22000', 'G22001',
                                            'G22002' )
                                AND TST.PT = 2
                                AND TST.RS < 3 THEN 2
                           ELSE 0
                      END ) AS B,
                   MAX ( CASE WHEN TST.PT IN ( 1, 2 )
                                AND TST.RS >= 3
                                AND CRS.CN NOT IN ( 'G21021', 'G21022',
                                                    'G21031', 'G21032',
                                                    'G21000', 'G21011',
                                                    'G21012', 'G22021',
                                                    'G22022', 'G22031',
                                                    'G22032', 'G22000',
                                                    'G22001', 'G22002' )
                           THEN 4
                           ELSE 0
                      END ) AS C
          FROM      MST
                    INNER JOIN STU
                    INNER JOIN SEC ON STU.SC = SEC.SC
                                      AND STU.SN = SEC.SN ON MST.SC = SEC.SC
                                                             AND MST.SE = SEC.SE
                    INNER JOIN CRS ON MST.CN = CRS.CN
                    INNER JOIN TST ON STU.ID = TST.PID
          WHERE     ( SEC.DEL = 0 )
                    AND ( TST.ID IN ( 'DST' ) )
                    AND ( TST.TA = 313 )
                    AND ( STU.ID = 4066398 )
                    AND ( STU.SC = 20 )
          GROUP BY  CRS.CN 
          
        ) AS d