SQL Avanzado

SELECT o.order_date,
       SUM(oi.quantity * oi.unit_price) AS ventas_del_dia,
       SUM(SUM(oi.quantity * oi.unit_price))
           OVER (ORDER BY o.order_date) AS total_acumulado
FROM orders o
JOIN order_items oi ON oi.order_id = o.order_id
WHERE o.status = 'completado'
GROUP BY o.order_date
ORDER BY o.order_date;