AggregateSQL standard

PERCENTILE_DISC

Finds a percentile among existing values — a median that's definitely in the data.

Syntax

PERCENTILE_DISC(<fraction>) WITHIN GROUP (ORDER BY <expression>)

Sorts the values and returns the first one at which the given share of rows is reached. Unlike PERCENTILE_CONT, it doesn't invent a midpoint between two values, so it works with dates and text too.

Data for the examples

employees

name	department	salary	bonus	phone
Emma	backend	1200	300	+44 7700 900123
Liam	backend	1000	NULL	NULL
Olivia	frontend	1350	150	+44 7700 900456
Noah	frontend	950	NULL	+44 7700 900789
Sophia	design	1200	200	NULL

orders

id	created_at	amount
1	2026-07-03 10:15:00	120.50
2	2026-07-28 18:40:00	80.25
3	2026-08-09 09:05:00	199.99
4	2026-08-21 14:30:00	45.00
5	2026-09-02 11:00:00	64.75

These tables already exist in the sandbox — the examples below use them. Want to try this in your own database? Copy the SQL.

The median salary

SELECT PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY salary) AS median_salary

FROM employees;

median_salary
1200

CONT versus DISC in each department

SELECT department,

PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY salary) AS cont,

PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY salary) AS disc

FROM employees

GROUP BY department

ORDER BY department;

department	cont	disc
backend	1100	1000
design	1200	1200
frontend	1150	950

backend has two salaries: CONT takes the midpoint between them — 1100, and DISC takes the smaller existing one, 1000.

The median order date

SELECT PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BY created_at) AS median_order

FROM orders;

median_order
2026-08-09 09:05:00

PERCENTILE_CONT doesn't work with dates, while DISC simply takes one of the existing ones.

Watch out

With an even number of values, it takes the smaller of the two middle ones: for 1000 and 1200 — 1000, not 1100.

The syntax is the same as in PERCENTILE_CONT: a fraction from 0 to 1 in the brackets, and the column in WITHIN GROUP (ORDER BY …).

It can't be a window function with OVER: OVER is not supported for ordered-set aggregate percentile_disc.

Related functions

PERCENTILE_CONT MIN NTILE