This page is a quick reference checkpoint for AVG OVER in MySQL: 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.
As a window function, AVG() returns the average value computed over the current window frame for each row rather than collapsing rows.
If this behavior feels unintuitive, the tutorial below explains the underlying pattern step-by-step.
AVG(expr) can be used as a window function with an OVER clause including optional PARTITION BY and ORDER BY.
SELECT AVG(salary) OVER (PARTITION BY dept ORDER BY salary) AS dept_avg FROM employees;
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 MySQL Documentation →Looking for more functions across all SQL dialects? Visit the full SQL Dialects & Window Functions Documentation.