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

select product_id,
product_name,
category_id,
sales_amount,
profit_rate
from (
    select p.product_id,
    product_name,
    category_id,
    sales_amount,
    round((sales_amount-cost_amount)/sales_amount,2) profit_rate,
    row_number() over (partition by category_id order by sales_amount desc) rk
    from product_category p
    join sales_and_profit s
    on p.product_id=s.product_id
) t
where profit_rate>0.2 and rk<=3
order by category_id, sales_amount desc, product_id