题解 | #计算商城中2021年每月的GMV#
统计2021年10月每个退货率不大于0.5的商品各项指标
http://www.nowcoder.com/practice/cbf582d28b794722becfc680847327be
select product_id, round(sum(if_click) / count(*),3) ctr, round(sum(if_cart) / sum(if_click),3) cart_rate, round(sum(if_payment) / sum(if_cart),3) payment_rate, round(sum(if_refund) / sum(if_payment),3) refund_rate from tb_user_event tb where date_format(event_time,'%Y-%m') = '2021-10' group by product_id having refund_rate <= 0.5 order by product_id
