DECLARE  
  TYPE nested_typ IS TABLE OF NUMBER;  
  
  nt1    nested_typ := nested_typ(1,2,3);  
  nt2    nested_typ := nested_typ(3,2,1);  
  nt3    nested_typ := nested_typ(2,3,1,3);  
  nt4    nested_typ := nested_typ(1,2,4);  
  answer nested_typ;  
  
  PROCEDURE print_nested_table (nt nested_typ) IS  
    output VARCHAR2(128);  
  BEGIN  
    IF nt IS NULL THEN  
      DBMS_OUTPUT.PUT_LINE('Result: null set');  
    ELSIF nt.COUNT = 0 THEN  
      DBMS_OUTPUT.PUT_LINE('Result: empty set');  
    ELSE  
      FOR i IN nt.FIRST .. nt.LAST LOOP  -- For first to last element  
        output := output || nt(i) || ' ';  
      END LOOP;  
      DBMS_OUTPUT.PUT_LINE('Result: ' || output);  
    END IF;  
  END  print_nested_table;  
  
BEGIN  
  answer := nt1 MULTISET UNION nt4;  
  print_nested_table(answer);  
  answer := nt1 MULTISET UNION nt3;  
  print_nested_table(answer);  
  answer := nt1 MULTISET UNION DISTINCT nt3;  
  print_nested_table(answer);  
  answer := nt2 MULTISET INTERSECT nt3;  
  print_nested_table(answer);  
  answer := nt2 MULTISET INTERSECT DISTINCT nt3;  
  print_nested_table(answer);  
  answer := SET(nt3);  
  print_nested_table(answer);  
  answer := nt3 MULTISET EXCEPT nt2;  
  print_nested_table(answer);  
  answer := nt3 MULTISET EXCEPT DISTINCT nt2;  
  print_nested_table(answer);  
END;