IBMi SQL Tips #22 - DB2 for i's hidden gems: OLAP functions

Sometimes, within an RPG program or a complex SQL query, there is a need to include a row counter, a running total, find a previous record, or create a ranking based on a specific value. This problem is often resolved using resource-intensive approaches, such as temporary work files, reopening SQL cursors, and so forth... There is a native tool within DB2 for i that handles all of this directly inside the database engine with incredible efficiency: OLAP (Online Analytical Processing) functions, also known as window functions. …