题解 |

select product_id,
round(COALESCE(sum(if_click)/count(product_id),0),3) as ctr,
round(COALESCE(sum(if_cart)/sum(if_click),0),3)as cart_rate,
round(COALESCE(sum(if_payment)/sum(if_cart),0),3) as payment_rate,
round(COALESCE(sum(if_refund)/sum(if_payment),0),3) as refund_rate
from tb_user_event
where year(event_time) = 2021 and month(event_time) = 10
group by product_id
having round(COALESCE(sum(if_refund)/sum(if_payment),0),3)<=0.5
order by product_id

isnull函数没办法通过