题解 | 查询出不同类别商品中，销售金额排名前三且利润率超过 20%的商品信息

with cte as (select p.product_id,product_name,category_id,sales_amount,round((sales_amount - cost_amount) / sales_amount,2) as profit_rate,row_number() over (partition by category_id order by sales_amount desc) as rnk
from product_category p
left join sales_and_profit using(product_id))

select product_id,product_name,category_id,sales_amount,profit_rate
from cte
where rnk <= 3 and profit_rate > 0.2
order by category_id,sales_amount desc,product_id