Warehouse SQL style

Tables:

• orders(id INTEGER, placed_at TEXT /* YYYY-MM-DD */, amount_cents INTEGER)
• refunds(order_id INTEGER, refunded_at TEXT, amount_cents INTEGER)

Rules:

1. Money is stored in cents. Divide by 100.0 only in the final projection.
2. Net revenue = SUM(o.amount_cents - COALESCE(r.amount_cents, 0)) with LEFT JOIN refunds r ON r.order_id = o.id.
3. Date ranges are half-open: placed_at >= :start AND placed_at < :end.
4. Always filter by date. A query without WHERE scans every order and needs a person's approval.