SELECT first_name||' '||last_name, (CASE
      WHEN manager_id IS NULL THEN 'MANAGER WITH NO MANAGER'
      WHEN manager_id IS NOT NULL AND manager_id NOT IN (SELECT m.employee_id FROM employees e, employees m WHERE e.employee_id=m.manager_id)  THEN 'MANAGER WITH MANAGER'
      WHEN manager_id IS NOT NULL AND manager_id IN (SELECT m.employee_id FROM employees e, employees m WHERE e.employee_id=m.manager_id)  THEN 'EMPLOYEE WITH MANAGER'
      WHEN manager_id IS NULL AND manager_id IN (SELECT m.employee_id FROM employees e, employees m WHERE e.employee_id=m.manager_id)  THEN 'EMPLOYEE WITH NO MANAGER'
      ELSE 'Няма такъв'
      END)
      FROM employees
      ORDER BY 2 DESC;