SET operatior in Oracle

SELECT Empno, Ename

FROM Emp

WHERE Deptno = 10

UNION

SELECT Empno, Ename

FROM Emp

WHERE Deptno = 30

ORDER BY 1;

SELECT Empno, Ename, Job

FROM Emp

WHERE Deptno = (SELECT Deptno

                FROM Dept

                WHERE Dname = 'SALES' ) 

UNION

SELECT Empno, Ename, Job

FROM Emp

WHERE Deptno = (SELECT Deptno

                FROM Dept

                WHERE Dname = 'ACCOUNTING')

ORDER BY 1;

SELECT Empno, Ename

FROM Emp

WHERE Deptno = 10 

UNION ALL

SELECT Empno, Ename

FROM Emp

WHERE Deptno = 30

ORDER BY 1;

SELECT Empno, Ename

FROM Emp

WHERE Deptno = 10 

INTERSECT

SELECT Empno, Ename

FROM Emp

WHERE Deptno = 30

ORDER BY 1;

SELECT Empno, Ename, Deptno

FROM Emp

WHERE Deptno = 10 

MINUS

SELECT Empno, Ename, Deptno

FROM Emp

WHERE Deptno = 30

ORDER BY 1;

SELECT Job

FROM Emp

WHERE Deptno = 20 

UNION

SELECT Job

FROM Emp

WHERE Deptno = 30;

SELECT Job

FROM Emp

WHERE Deptno = 20 

UNION

SELECT Job

FROM Emp

WHERE Deptno = 30;

SELECT Job

FROM Emp

WHERE Deptno = 20 

INTERSECT

SELECT Job

FROM Emp

WHERE Deptno = 30;

SELECT Job

FROM Emp

WHERE Deptno = 20

MINUS

SELECT Job

FROM Emp

WHERE Deptno = 10;

SELECT ROWNUM, Ename

FROM Emp

WHERE ROWNUM < 7

MINUS

SELECT ROWNUM, Ename

FROM Emp

WHERE ROWNUM < 6;