-- Using Select Case
SELECT CASE
WHEN G.Grade > 7
THEN CONCAT(S.NAME, ' ', G.Grade, ' ', S.Marks)
ELSE CONCAT('NULL', ' ', G.Grade, ' ', S.Marks)
END
AS 'Tab'
FROM
Students S 
JOIN Grades G
WHERE S.Marks BETWEEN G.Min_Mark and G.Max_Mark
ORDER BY G.Grade DESC, S.NAME;

            -- Simplified Solution
SELECT IF(Grade > 7 , Name, 'NULL'), Grade, Marks
FROM Students JOIN Grades
WHERE Marks BETWEEN Min_Mark and Max_Mark
ORDER BY Grade DESC, Name;