Level 5 - SeniorScenario-Based Questions
Scenario: Daily Incremental Aggregate Refresh
Interviewer prompt: You maintain daily_sales_summary. Recomputing full history is too slow. Write SQL approach for incremental refresh using last successful watermark.
Schema Context
orders(order_id, order_ts, status, total_amount), etl_watermark(job_name, last_run_ts)