Document if width_bucket's low and high are inclusive/exclusive

Ben Peachey Higdon <bpeacheyhigdon@gmail.com>

From: Ben Peachey Higdon <bpeacheyhigdon@gmail.com>
To: pgsql-docs@lists.postgresql.org
Date: 2025-02-28T01:31:59Z
Lists: pgsql-docs
The current documentation for width_bucket (https://www.postgresql.org/docs/current/functions-math.html <https://www.postgresql.org/docs/current/functions-math.html>) does not mention if the range’s low and high are inclusive or exclusive.

> Returns the number of the bucket in which operand falls in a histogram having count equal-width buckets spanning the range low to high. Returns 0 or count+1 for an input outside that range.


I had assumed that both the low and high were inclusive but actually the low is inclusive while the high is exclusive.

For example:
SELECT width_bucket(0, 0, 1, 4)

returns 1, the first of 4 bins

SELECT width_bucket(1, 0, 1, 4) 

returns 5, because the high was outside the exclusive bound of high = 1

Thank you!

Commits

  1. Doc: improve documentation about width_bucket().