显示在30号部门工作的雇员的名字和他上司的名字( )。 EMP(EMPNO,ENAME,JOB,MGR,HIREDATE,SAL,COMM,DEPTNO)
A.
Select e.ename,s.ename from emp e,emp s where e.deptno =30 and e.empno=s.mgr
B.
Select ename,ename from emp join emp on deptno =30 and empno=mgr
C.
Select e.ename,s.ename from emp e join emp s on deptno =30 and e.empno=s.mgr
D.
Select e.ename,s.ename from emp e,emp s where e.deptno =30 and s.empno=e.mgr