select period ,count(*) car_num ,round(avg(wait_time),1) avg_wait_time ,round(avg(dispatch_time),1) avg_wait_time from( select timestampdiff(second,t1.event_time,t1.end_time)/60 wait_time,timestampdiff(second,t2.order_time,t2.start_time)/60 dispatch_time ,case when date_format(event...