PostgreSQL 18 reference · Math Functions

PostgreSQL FLOOR() Function

Round a number down to the nearest integer: floor(2.9) is 2 and floor(-2.1) is -3.

PostgreSQL 18

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Syntax

floor(x)

Parameter	Description
`x`	A number (`integer`, `numeric` or `double precision`).

A number of the input type.

Round down

SELECT floor(2.9) AS a, floor(-2.1) AS b;

Output

 a | b
---+----
 2 | -3
(1 row)

Run this on your computer — see “Get Started” for setup.

Price bands

SELECT floor(price / 10) * 10 AS band, count(*) AS products
FROM products
GROUP BY band
ORDER BY band
LIMIT 4;

Output

 band | products
------+----------
    0 |        1
   10 |        1
   20 |        2
   30 |        2
(4 rows)

Run this on your computer — see “Get Started” for setup.

CEIL() · Round a number up to the nearest integer: ceil(2.1) is 3 and ceil(-2.1) is -2. ceiling() is a synonym.
TRUNC() · Truncate a number toward zero, optionally keeping some decimal places: trunc(2.789, 2) is 2.78.
WIDTH_BUCKET() · Return which of n equal-width buckets a value falls into between a low and high bound, for building histograms.
SQL Aggregate Functions · tutorial