select
a.job
,case when mod(max(a.r),2) = 0 then ceiling(max(a.r)/2) else ceiling(max(a.r)/2) end
,case when mod(max(a.r),2) = 0 then ceiling(max(a.r)/2+1) else ceiling(max(a.r)/2) end
from (
select
g.*
,row_number() over(partition by g.job order by score) r
from grade g
) a
group by a.job
order by a.job