A. SELECT StudentCode as Code, RANK() OVER(ORDER BY AVG(Marks) DESC) AS Value FROM StudentMarks GROUP BY StudentCode

B. SELECT Id, Name, Marks, DENSE_RANK() OVER(ORDER BY Marks DESC) AS Rank FROM StudentMarks

C. SELECT StudentCode as Code, DENSE_RANK() OVER(ORDER BY AVG(Marks) DESC) AS Value FROM StudentMarks
GROUP BY StudentCode

D. SELECT StudentCode as Code, NTILE(2) OVER(ORDER BY AVG(Marks) DESC) AS Value FROM StudentMarks GROUP BY StudentCode

E. SELECT StudentCode AS Code, Marks AS Value FROM (
SELECT StudentCode, Marks AS Marks,
RANK() OVER(PARTITION BY SubjectCode ORDER BY Marks ASC) AS Rank
FROM StudentMarks) tmp
WHERE Rank = 1

F. SELECT StudentCode AS Code, Marks AS Value FROM (
SELECT StudentCode, Marks AS Marks,
RANK() OVER(PARTITION BY SubjectCode ORDER BY Marks DESC) AS Rank
FROM StudentMarks) tmp
WHERE Rank = 1

G. SELECT StudentCode AS Code, Marks AS Value FROM (
SELECT StudentCode, Marks AS Marks,
RANK() OVER(PARTITION BY StudentCode ORDER BY Marks ASC) AS Rank
FROM StudentMarks) tmp
WHERE Rank = 1

H. SELECT StudentCode AS Code, Marks AS Value FROM (
SELECT StudentCode, Marks AS Marks,
RANK() OVER(PARTITION BY StudentCode ORDER BY Marks DESC) AS Rank
FROM StudentMarks) tmp
WHERE Rank = 1