This page is a quick reference checkpoint for AVG OVER in IBM DB2: 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.
AVG() OVER(...) returns the average of the applicable values in the partition or defined window; nulls are ignored (unless all values in the set are null, in which case result is null). Aggregation-specification (window-aggregate) cannot be used in WHERE, VALUES, GROUP BY, HAVING, SET, or as argument to another aggregate.
If this behavior feels unintuitive, the tutorial below explains the underlying pattern step-by-step.
AVG() can be used with an OVER(...) clause as part of the OLAP aggregation-specification
SELECT MIN(balance) OVER (PARTITION BY customer_id) FROM accounts;
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 IBM DB2 Documentation →Looking for more functions across all SQL dialects? Visit the full SQL Dialects & Window Functions Documentation.