Black Friday month: the 7-day rolling average

November is the peak of the shopping year, but many days have no sales at all, and a naive GROUP BY simply skips them. The pricing team wants a smooth view: net revenue per calendar day of November 2025 (zero on days without sales) and the average of the current day and the 6 days before it. Table notes: a line's net revenue is quantity * unit_price * (1 - discount_pct / 100.0). Orders with status Cancelled never count as sales.

Task: build a calendar with a recursive CTE starting at 2025-10-25 (so that early November has a full 7-day window) up to 2025-11-30, left join daily revenue, and return only November days as day, revenue (0 when no sales) and avg_7d (trailing 7-day average including today, counting zero days). Use ROUND(x, 2) on both numbers. Sort by day, oldest first.