SELECT product_id,
    if(count(*)=0,0,round(sum(if_click)/count(*),3))ctr,
    if(sum(if_click)=0,0,round(sum(if_cart)/sum(if_click),3))cart_rate,
    if(sum(if_cart)=0,0,round(sum(if_payment)/sum(if_cart),3))payment_rate,
    if(sum(if_payment)=0,0,round(sum(if_refund)/sum(if_payment),3))refund_rate
FROM tb_user_event
WHERE year(event_time)=2021 AND month(event_time)=10
GROUP BY product_id
HAVING refund_rate<=0.500
ORDER BY product_id ASC;