SELECT
    CASE
        WHEN GRADES.GRADE >= 8 THEN STUDENTS.NAME
        ELSE NULL
    END, GRADES.GRADE, STUDENTS.MARKS
FROM STUDENTS
JOIN GRADES
ON STUDENTS.MARKS BETWEEN GRADES.MIN_MARK AND GRADES.MAX_MARK
ORDER BY GRADES.GRADE DESC,
    (CASE
        WHEN GRADES.GRADE >= 8 THEN STUDENTS.NAME
        ELSE STUDENTS.MARKS
    END);