20-Minute Joins and KPI Sprint

This sprint focuses on fanout-safe joins and KPI rollups.

Time budget:

• 0-8 min: Drill 1
• 8-20 min: Drill 2

For completed orders, return category-level metrics.

Required output columns:

• category
• completed_orders
• revenue

Build month-level gross, returned, and net revenue.

Attribution rule: attribute each return to the month of the original order (link returns to order items via order_item_id, and take the month from the order's order_date) - not to the month the return was filed. This keeps gross, returned, and net consistent within each month.

Required output columns:

• month_start
• gross_revenue (rounded to 2 decimals)
• returned_amount (rounded to 2 decimals)
• net_revenue (rounded to 2 decimals; equals gross_revenue - returned_amount)