CREATE TABLE Customer_Orders (Actual_Delivery_Date VARCHAR2, Order_ID VARCHAR2)
CREATE TABLE ORDER_ITEMS (Order_ID VARCHAR2, Order_Quantity VARCHAR2)

What are the actual delivery dates of orders with quantity 1?
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
SELECT "T1"."Actual_Delivery_Date" FROM "Customer_Orders" "T1" JOIN "ORDER_ITEMS" "T2" ON "T1"."Order_ID" = "T2"."Order_ID" AND "T2"."Order_Quantity" = 1