Yes
select t1.actual_delivery_date from customer_orders as t1 join order_items as t2 on t1.order_id = t2.order_id where t2.order_quantity = 1
What are the product id of orders with quantity 1?
select product_id from order_items where order_quantity = 1
Ok ,, what are the cuatomers id that have order of quantity 1?
select t1.customer_id from customer_orders as t1 join order_items as t2 on t1.order_id = t2.order_id where t2.order_quantity = 1