One row per window (hourly, daily, weekly, monthly) — latest period for each. Use the filter to focus on one window.
Store SQL on all orders in window: volume = COUNT(*); avg_tip% same baseline formula as employee; avg_bill = AVG(bill/100); refund_rate = refunds/volume.
Peak hours: COUNT(*) grouped by UTC hour of ingested_at; the UI converts hour labels to your browser timezone.