DENSE_RANK

select
  id,
  salary,
  dense_rank() over (order by salary)
from employee
order by salary;

Result

id salary dense_rank
-- ------ ----------
 3  8.00           1
 4  9.00           2
 1 10.00           3
 5 10.00           3
 2 12.00           4

Distributes the rows of the current window partition into the specified number of tiles (groups)

Result type

BIGINT

Syntax

NTILE ( number_of_tiles ) OVER <window_name_or_spec>

Table 1. Arguments of `NTILE`
Argument	Description
number_of_tiles	Number of tiles (groups).Restricted to a positive integer literal, a named parameter (PSQL), or a positional parameter (DSQL).