What is NTILE(), in MS SQL Server?

Answer 1

Oh, it is simple!

NTILE() can be used to split the set into equal groups.

SELECT Ratings
                ,NTILE(2) OVER(ORDER BY Ratings) AS NTILE
    FROM  RatingsTable

Ratings NTILE
----------- --------------------
1           1
1           1
2           1
2           1
3           1
3           2
3           2
3           2
3           2
3           2