NTILE() Function | SQL Server | SQL Tutorial

The NTile function takes an integer as an input and divides the records of the result set into that number of groups.
In case the result set is not exactly divisible into an equal number of records, it assigns more records to the starting groups and less to the following ones.
within each group, each record will have the same number or rank.
CASE 1: Ranking entire result set using Order By clause.
CASE 2: Ranking partitioned result set using Partition By Clause

ROW_NUMBER in SQl Server:

Rank and Dense Rank in SQL Server: