Ranking, Sql Server

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--You create a table that has the StudentCode, SubjectCode, and Marks columns to record mid-year marks for students.
--The table has marks obtained by 50 students for various subjects.
--You need to ensure that the top half of the students arranged by their average marks must be given a rank of 1 
--and the remaining students must be given a rank of 2. Which Transact-SQL query should you use?

create table student(StudentCode int, SubjectCode int,  Marks int)

insert into student values  (1,1,10),(1,2,20),(1,3,30)
                           ,(2,1,30),(2,2,40),(2,3,50)
                           ,(3,1,40),(3,2,50),(3,3,50)
                           ,(4,1,40),(4,2,50),(4,3,50)

select StudentCode,dense_rank() over(order by avg(marks) desc) as rank from student group by studentcode

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

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

-- get subjectcode,studentcode, marks of those who have maximum marks in each subject

select StudentCode , SubjectCode ,  Marks from(
select StudentCode , SubjectCode ,  Marks,rank() over (partition by subjectcode order by marks desc ) as rank  from student) tmp
where tmp.rank=1

View schema
Execution time: 0 sec, rows selected: 12, rows affected: 12, absolute service time: 0.14 sec