把上一个结果改一点点就了。
SELECT dname,grade,c
FROM dept,(SELECT deptno,grade,c,ROWNUM r
FROM (SELECT deptno,grade,c
FROM (SELECT deptno,avg(sal) c
FROM emp GROUP BY deptno),salgrade
WHERE c BETWEEN losal AND hisal ORDER BY grade DESC) t
WHERE ROWNUM<=2) t
WHERE dept.deptno=t.deptno AND r=2;