select
    b.department,
    concat(round(sum(if(timestampdiff(second,a.first_clockin,a.last_clockin)/3600 >9.5,1,0)) / 
    count(distinct a.staff_id)*100,1),'%') as ratio
from
    attendent_tb a
left join
    staff_tb b on a.staff_id = b.staff_id
group by
    1 
order by
    2 desc;