SELECT 
    CASE
        WHEN G.Grade < 8 THEN 'NULL'
        ELSE S.Name
    END AS Name,
    G.Grade,
    S.Marks
FROM 
    Students S
JOIN 
    Grades G ON S.Marks BETWEEN G.Min_Mark AND G.Max_Mark
ORDER BY 
    G.Grade DESC,
    CASE
        WHEN G.Grade >= 8 THEN S.Name
        ELSE NULL
    END ASC,
    CASE
        WHEN G.Grade < 8 THEN S.Marks
        ELSE NULL
    END ASC;