摘要：
1.平均薪水的等级最低的部门的部门名称:select dname from( select avg_sal, deptno, grade from (select avg(sal) avg_sal,deptno from emp group by deptno) join salgrade on avg_sal between salgrade.losal and salgrade.hisal) t1join dept on t1.deptno=dept.deptnowhere t1.grade=( select min(grade) from ( sel... 阅读全文
