SELECTrequest_at,round(count(if(status='cancelled_by_driver',id,NULL))/count(id),2) as cancel_rate-- a.*,b.client_is_bannd,b.driver_is_banndFROM(select*from leetcode.ex_262_trips wherestatus<>'cancelled_by_client') a join(select*from leetcode.ex_262_users whererole='client'and banned ='No') b ON a.client_id=b.users_idjoin(select*from leetcode.ex_262_users whererole='driver'and banned ='No') c ON a.driver_id=c.users_idgroup by request_at ;