Analytical Function:-

return the infornation that about the relative possition of record (ROW_NUMBER Rank DENSE_RANK) and allow to campare with succesor and precedessors when they sort in spacific order.

select ename deptno sal hiredate row_number() over ( partition by deptno order by sal desc comm desc hiredate desc
) sal_rank_in_dept row_number() over (order by sal desc) sal_rank_overall
from emp
order
by deptno
sal desc
comm desc
hiredate desc