This page is a quick reference checkpoint for AVG OVER in Postgres: behavior, syntax rules, edge cases, and a minimal example; plus the official vendor documentation.
AVG OVER returns the average value of an expression across the window frame.
When an aggregate function like AVG is used with ORDER BY and the default frame, it computes a running aggregate from the start of the partition to the current row (including peers).
If this behavior feels unintuitive, the tutorial below explains the underlying pattern step-by-step.
Any built-in or user-defined ordinary aggregate (such as AVG) can be used as a window function with an OVER clause.
SELECT AVG(salary) OVER (PARTITION BY department ORDER BY salary) FROM empsalary;
If you came here to confirm syntax, you’re done. If you came here to get better at window functions, choose your next step.
AVG OVER is part of a bigger window-function pattern. If you want the “why”, start here: Aggregate Window Functions
Reading docs is useful. Writing the query correctly under pressure is the skill.
For the authoritative spec, use the vendor docs. This page is the fast “sanity check”.
View Postgres Documentation →Looking for more functions across all SQL dialects? Visit the full SQL Dialects & Window Functions Documentation.