This page is a quick reference checkpoint for MAX OVER in IBM DB2: behavior, syntax rules, edge cases, and a minimal example; plus the official vendor documentation.
MAX OVER returns the largest value in the window frame.
MAX() OVER(...) returns the maximum value in the partition or in the defined window frame. NULL values are ignored (unless all values are NULL, in which case result is NULL). Aggregation-specification 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.
MAX() can be used with an OVER(...) clause as part of the OLAP aggregation-specification
SELECT MAX(score) OVER (PARTITION BY class) FROM exam_results;
If you came here to confirm syntax, you’re done. If you came here to get better at window functions, choose your next step.
MAX 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.