equi-join

SELECT ename, job, dept.deptno, dname

FROM emp, dept
 WHERE emp.deptno = dept.deptno;

SELECT *
  FROM emp, dept
 WHERE emp.deptno = dept.deptno
   AND job = 'CLERK';

Using ANSI join syntax:

SELECT ename, dname
 FROM emp INNER JOIN dept
   ON emp.deptno = dept.deptno