WITH item_counts AS (SELECT order_id,COUNT(*) AS item_rows FROM order_items GROUP BY order_id) SELECT SUM(o.total_cents-o.refund_cents) AS net_cents FROM orders o LEFT JOIN item_counts i ON i.order_id=o.id WHERE o.status='paid' AND o.order_date>='2026-09-01' AND o.order_date<'2026-10-01';