FirebirdSQL logo
 Aggregate FunctionsSystem Packages 

NTILE Examples

select
  id,
  salary,
  rank() over (order by salary),
  ntile(3) over (order by salary)
from employee
order by salary;
Result
ID SALARY RANK NTILE
== ====== ==== =====
 3   8.00    1     1
 4   9.00    2     1
 1  10.00    3     2
 5  10.00    3     2
 2  12.00    5     3

PERCENT_RANK()

Relative rank of a row within a window partition.

Result type

DOUBLE PRECISION

Syntax
PERCENT_RANK () OVER <window_name_or_spec>

PERCENT_RANK is calculated as the [fblangref50-windowfuncs-rank] minus 1 of the current row divided by the number of rows in the partition minus 1.

In other words, PERCENT_RANK() OVER <window_name_or_spec> is equivalent to (RANK() OVER <window_name_or_spec> - 1) / CAST(COUNT(*) OVER() - 1 AS DOUBLE PRECISION)