题解 | 统计各岗位员工平均工作时长

select
    # s.staff_id,	
    post,
    # first_clockin,
    # last_clockin,
    # avg(TIMESTAMPDIFF(minute, first_clockin,last_clockin)/60) as work_hours
    avg((UNIX_TIMESTAMP(last_clockin ) - UNIX_TIMESTAMP(first_clockin)) / 3600 ) as work_hours

from staff_tb s
join attendent_tb a on s.staff_id = a.staff_id
where first_clockin is not null and last_clockin is not null
group by post
order by work_hours desc

两种方法：

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（1）

TIMESTAMPDIFF(minute, first_clockin, last_clockin)/60

（2）

(UNIX_TIMESTAMP(last_clockin ) - UNIX_TIMESTAMP(first_clockin)) / 3600