select 
t1.order_id
,t2.customer_name customer_name
,t1.order_date  order_date
from 
(
	select
	order_id
	,customer_id
	,order_date
	,rank()over(partition by customer_id order by order_date desc) r 
	from orders
) t1
join customers t2
on t1.customer_id = t2.customer_id
where r = 1
order by 2