题解 | 查询出每个品牌在特定时间段内的退货率以及平均客户满意度评分

select a.brand_id, brand_name,
round(sum(case when return_status=1 then 1 else 0 end) / count(1), 2) as return_rate_July_2024,
round(avg(customer_satisfaction_score), 2) as average_customer_satisfaction_score
from brand_info a
join (
    select *
    from sales_orders
    where year(order_date)=2024 and month(order_date)=7
) b on a.brand_id=b.brand_id
join customer_feedback c on b.order_id=c.order_id
group by a.brand_id, brand_name
order by a.brand_id