Want to learn more on NTILE()

Question

I was reading on RANKING function for ms sql. I understand the others function except NTILE(). Lets say if i have this data:

   StudentID     MARKS  
              


        

Answer 1

It will arrange the data in descending order of marks and then split it into 2 groups.

If the data cannot be split into equal groups, then the first few groups will have more rows than the latter groups.

So NTILE(2) will give you

StudentID       MARKS       NTILE  
      S5           93           1 
      S3           91           1 
      S2           83           1
      S4           83           2
      S1           75           2 

Similarly NTILE(3) will give you

StudentID       MARKS       NTILE  
      S5           93           1 
      S3           91           1 
      S2           83           2
      S4           83           2
      S1           75           3