题解 | #统计各岗位员工平均工作时长#

select 
post,
round(avg(timestampdiff(second,b.first_clockin,b.last_clockin) / 3600),3) as work_hours
from staff_tb a
join attendent_tb b on a.staff_id=b.staff_id
where b.first_clockin is not null and b.last_clockin is not null
group by post
order by work_hours desc;