Find all the customer orders that made before 2018-03-17 07:13:53.
select * from customer_orders where order_date < '2018-03-17 07:13:53'
Compute the total quantity of items purchased in this order.
select sum(t2.order_quantity) from customer_orders as t1 join order_items as t2 on t1.order_id = t2.order_id where t1.order_date < '2018-03-17 07:13:53'