create or replace type t_empno as object (
    empno integer
)
/
create or replace type tbl_empno as table of t_empno;
/
create or replace package pkg_test as
  function getEmp return tbl_empno;
  procedure deleteEmp;
  procedure addEmp(p_empno integer);
end;
/
create or replace package body pkg_test as

  v_empno tbl_empno := tbl_empno();

  function getEmp return tbl_empno as
  begin
    return v_empno;
  end;

  procedure deleteEmp as
  begin
    v_empno.delete;
  end;

  procedure addEmp(p_empno integer) as
  begin
    v_empno.extend;
    v_empno(v_empno.count) := t_empno(p_empno);
  end;
end;
/

sql> exec pkg_test.deleteEmp;

PL/SQL procedure successfully completed.

sql> exec pkg_test.addEmp( 7369 );

PL/SQL procedure successfully completed.

sql> exec pkg_test.addEmp( 7499 );

PL/SQL procedure successfully completed.

sql> select e.empno, e.ename, e.job
   2   from scott.emp e
   3          inner join table(cast(pkg_test.getEmp as tbl_empno)) v
   4            on e.empno = v.empno;

     EMPNO ENAME      JOB
 ---------- ---------- ---------
 
       7369  SMITH      CLERK
       7499  ALLEN      SALESMAN