题解 | 每个顾客购买的最新产品名称

select customer_id,customer_name,product_name as latest_order
from(
	select a.customer_id,customer_name,product_name,dense_rank()over(partition by a.customer_id order by order_date desc) as rk
	from orders a
	left join customers b using(customer_id)
	left join products c using(product_id))d
where rk =1
order by customer_id

窗口函数排序+子查询挑出最新信息