This page is a quick reference checkpoint for ROW_NUMBER in IBM DB2: behavior, syntax rules, edge cases, and a minimal example; plus the official vendor documentation.
ROW_NUMBER assigns a unique sequential number to each row within the window partition.
Numbers rows sequentially beginning with 1 based on the ORDER BY clause; no ties because each row always receives a distinct row number.
If this behavior feels unintuitive, the tutorial below explains the underlying pattern step-by-step.
Requires ORDER BY in the OLAP specification; assigns a unique sequential integer to each row within the partition.
SELECT ROW_NUMBER() OVER (PARTITION BY dept ORDER BY salary) AS row_num 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.
ROW_NUMBER is part of a bigger window-function pattern. If you want the “why”, start here: Ranking 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.