题解 | 统计快递运输时长

select info.exp_type,round(avg(timestampdiff(minute, trans.out_time, trans.in_time) / 60),1) as time
from express_tb as info
inner join exp_action_tb as trans
on  info.exp_number = trans.exp_number
group by info.exp_type
order by time 

timestampdiff(minute, trans.out_time, trans.in_time) / 60

一定要记住这个时间相减计算小时的这个公式了了呀！