select salgrade.grade ,t.deptno from
(select avg(sal) as avg_sal ,deptno from emp group by deptno ) t join salgrade on (t.avg_sal between salgrade.losal and hisal);
select salgrade.grade ,t.deptno from
(select avg(sal) as avg_sal ,deptno from emp group by deptno ) t join salgrade on (t.avg_sal between salgrade.losal and hisal);