SELECT emp.last_name, CASE WHEN manager.manager_id IS NULL THEN 'Manager without manager'
ELSE 'Manager with manager'
END STATUS
FROM employees emp
INNER JOIN employees manager
ON emp.manager_id = manager.employee_id
UNION ALL
SELECT last_name, CASE WHEN manager_id IS NOT NULL THEN 'Employee with manager'
ELSE 'Employee without manager'
END STATUS
FROM employees
ORDER BY 2 DESC;