Show me the orders placed between 2009-01-01 and 2010-01-01.
select * from orders where date_order_placed >= "2009-01-01" and date_order_placed <= "2010-01-01"
Show me the customers who made those orders.
select t1.customer_name from customers as t1 join orders as t2 on t1.customer_id = t2.customer_id where t2.date_order_placed >= "2009-01-01" and t2.date_order_placed <= "2010-01-01"