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
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
https://www.nowcoder.com/practice/39f4ccb8ac1b47a89d092b4d8ed08bc8
SELECT b.brand_id,
b.brand_name,
ROUND(AVG(s.return_status),2) as return_rate_July_2024,
ROUND(AVG(c.customer_satisfaction_score),2) as average_customer_satisfaction_score
FROM sales_orders as s
LEFT JOIN brand_info as b
USING(brand_id)
LEFT JOIN customer_feedback as c
USING(order_id)
WHERE s.order_date LIKE "2024-07%"
GROUP BY b.brand_id
ORDER BY brand_id ASC
注意，对于0-1分类变量，求平均值即为求label=1的比例，所以直接对return_status求AVG()即可，无需SUM()/COUNT(*).
