题解 | 查询出每个品牌在不同月份的总销售额以及购买该品牌商品的用户的平均年龄

   select  distinct category_id ,sum(order_amount)  as total_sales ,
            sum(if(customer_gender ='男',1,0)) as male_customers,
             sum(if(customer_gender ='女',1,0)) as female_customers
    from order_details inner join
        customer_info  on order_details.order_id =customer_info.order_id
    where  order_date >'2024-01-01' and order_date <'2024-06-30'
    group by  category_id,customer_gender
    order by  category_id