关于Oracle数据库删除、查询(三):select a1.ename,a1.sal,a2.grade from emp a1,salgrade a2 where a1.sal between a2.losal and a2.hisal; select worker.ename,boss.ename from emp worker,emp boss where worker.mgr=boss.empno and worker.mgr='FOLD'; select * from emp where deptno=(