select * from departments order by dept_no; select * from departments_dup order by dept_no; select * from departments union select * from departments_dup order by dept_no; select * from employees; select * from dept_manager; select emp_no, first_name, last_name, null as dept_no from employees union select null as emp_no, null as first_name, null as last_name, dept_no from dept_manager;