SELECT e.employee_id,
    e.first_name||' '|| e.last_name AS name,
    CONNECT_BY_ROOT e.manager_id managerID,
    CONNECT_BY_ROOT (e1.first_name||' '||e1.last_name) manager,
    LEVEL AS начальников,
    sys_connect_by_path(e1.first_name||' '||e1.last_name, ' / ') AS MANAGER_PATH
    FROM employees e
    join employees e1 ON e.manager_id=e1.employee_id
    CONNECT BY e.manager_id=PRIOR e.employee_id
    ORDER BY name, LEVEL DESC;