This page is a quick reference checkpoint for AVG OVER in BigQuery: 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.
Returns the average of non-NULL values in a group; when used with OVER it becomes a window function. If group is empty or all values NULL, returns NULL; if any argument is NaN, returns NaN; if floating-point result type, result may be non-deterministic.
If this behavior feels unintuitive, the tutorial below explains the underlying pattern step-by-step.
AVG([ DISTINCT ] expression) [ OVER (window_clause) ]
SELECT team, score, AVG(score) OVER (PARTITION BY team) AS team_avg_score FROM games_table;
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 BigQuery Documentation →Looking for more functions across all SQL dialects? Visit the full SQL Dialects & Window Functions Documentation.