SELECT Top 1 SUM(Marks) TotalMarks, M.STUDENT_ID, S.STUDENT_NAME, S.CLASS
FROM Student_Marks M
JOIN STUDENT S ON S.STUDENT_ID=M.STUDENT_ID
WHERE M.EXAM_ID = ( SELECT EXAM_ID FROM SUBJECT_EXAM where EXAM_NAME = 'Half-yearly')
GROUP BY M.STUDENT_ID , S.STUDENT_NAME, S.CLASS
ORDER BY TotalMarks DESC