SQL: Window Function to Rank Within Group

Given events(user_id INT, event_time TIMESTAMP, event_type STRING, revenue DECIMAL(10,2)), write an SQL query to find each user's most recent event. Output: user_id event_time event_type revenue Requirements: If multiple events share the same timestamp for a user, pick the one with higher revenue as the most recent. Use a window function such as ROW_NUMBER(). Data scale: up to 100M rows. Validation cases: Multiple events per user -> pick max event_time Same event_time -> pick max revenue Multiple users -> one row per user revenue may be NULL -> treat NULL as smallest Example Input events: (1,'2025-01-01 10:00:00','click',NULL) (1,'2025-01-01 11:00:00','purchase',20.0) (2,'2025-01-01 09:00:00','click',0.0) Output 1 2025-01-01 11:00:00 purchase 20.0 2 2025-01-01 09:00:00 click 0.0