SQL> --PRƯNT ODD NUMBERS FROM 0 TO 10
SQL> ED
Wrote file afiedt.buf

  1  DECLARE
  2    COUNTER NUMBER;
  3  BEGIN
  4    COUNTER :=1;
  5    WHILE COUNTER<=10
  6     LOOP
  7       DBMS_OUTPUT.PUT_LINE(COUNTER);
  8       COUNTER := COUNTER+2;
  9     END LOOP;
 10* END;
SQL> /
1                                                                               
3                                                                               
5                                                                               
7                                                                               
9                                                                               

PL/SQL procedure successfully completed.

SQL> ED
Wrote file afiedt.buf

  1  DECLARE
  2    COUNTER NUMBER;
  3  BEGIN
  4    COUNTER :=10;
  5    WHILE COUNTER>=1
  6     LOOP
  7       DBMS_OUTPUT.PUT_LINE(COUNTER);
  8       COUNTER := COUNTER-2;
  9     END LOOP;
 10* END;
SQL> /
10                                                                              
8                                                                               
6                                                                               
4                                                                               
2                                                                               

PL/SQL procedure successfully completed.

SQL> ED
Wrote file afiedt.buf

  1  DECLARE
  2    COUNTER NUMBER;
  3  BEGIN
  4    COUNTER :=9;
  5    WHILE COUNTER>=1
  6     LOOP
  7       DBMS_OUTPUT.PUT_LINE(COUNTER);
  8       COUNTER := COUNTER-2;
  9     END LOOP;
 10* END;
SQL> /
9                                                                               
7                                                                               
5                                                                               
3                                                                               
1                                                                               

PL/SQL procedure successfully completed.

SQL> ED
Wrote file afiedt.buf

  1  BEGIN
  2  FOR COUNTER IN REVERSE 10 .. 1
  3     LOOP
  4      IF MOD(COUNTER,2)=1 THEN
  5       DBMS_OUTPUT.PUT_LINE(COUNTER);
  6      END IF;
  7     END LOOP;
  8* END;
SQL> /

PL/SQL procedure successfully completed.

SQL> ED
Wrote file afiedt.buf

  1  BEGIN
  2  FOR COUNTER IN REVERSE 1 .. 10
  3     LOOP
  4      IF MOD(COUNTER,2)=1 THEN
  5       DBMS_OUTPUT.PUT_LINE(COUNTER);
  6      END IF;
  7     END LOOP;
  8* END;
SQL> /
9                                                                               
7                                                                               
5                                                                               
3                                                                               
1                                                                               

PL/SQL procedure successfully completed.

SQL> --READ TWO NUMBERS FROM KEYBOARD AND PRINT WHETHER FIRST IS BIGGER, SECOND IS BIGGER OR
SQL> --WHETHER THEY ARE EQUAL
SQL> ED
Wrote file afiedt.buf

  1  DECLARE
  2    NUM1 NUMBER := &FIRSTNUM;
  3    NUM2 NUMBER := &SECONDNUM;
  4  BEGIN
  5    IF NUM1 < NUM2 THEN
  6      DBMS_OUTPUT.PUT_LINE('SECOND NUMBER IS BIGGER');
  7    ELSIF NUM1 > NUM2 THEN
  8      DBMS_OUTPUT.PUT_LINE('FIRST NUMBER IS BIGGER');
  9    ELSE
 10      DBMS_OUTPUT.PUT_LINE('EQUALLLL');
 11    END IF;
 12* END;
SQL> /
Enter value for firstnum: 4
old   2:   NUM1 NUMBER := &FIRSTNUM;
new   2:   NUM1 NUMBER := 4;
Enter value for secondnum: 5
old   3:   NUM2 NUMBER := &SECONDNUM;
new   3:   NUM2 NUMBER := 5;
SECOND NUMBER IS BIGGER                                                         

PL/SQL procedure successfully completed.

SQL> SPOOL OFF