Why SQL Window Functions Outperform Self-Joins

In this episode of Database Tech with Fexingo, Lucas and Luna break down a real-world query optimization: replacing a self-join with a SQL window function to compute running totals. They discuss how window functions like ROW_NUMBER, RANK, and LEAD reduce query time from seconds to milliseconds by eliminating multiple table scans. Lucas explains the OVER clause, partitioning, and ordering, and contrasts with subquery alternatives. They cover when window functions shine (analytics, rankings, moving averages) and when traditional joins might still be better. This episode includes a concrete example from a client where a 12-second query dropped to under a second. Ideal for data engineers, analysts, and SQL developers looking to improve query performance and code readability. #SQL #WindowFunctions #QueryOptimization #DataEngineering #Performance #SelfJoin #Subquery #PostgreSQL #MySQL #Snowflake #RunningTotal #Analytics #DatabaseTech #Technology #FexingoBusiness #BusinessPodcast #Engineering #DataAnalytics Keep every episode free: buymeacoffee.com/fexingo