SELECT z.ID_ZESP, p.ETAT, ROUND(AVG(NVL(p.PLACA_POD + p.PLACA_DOD, p.PLACA_POD))) AS SREDNIA, ROUND(MAX(NVL(p.PLACA_POD + p.PLACA_DOD, p.PLACA_POD))) AS MAKSYMALNA
FROM PRACOWNICY p, ZESPOLY z
WHERE p.ID_ZESP = z.ID_ZESP AND (p.ETAT = 'ASYSTENT' OR p.ETAT = 'PROFESOR')
GROUP BY z.ID_ZESP, p.ETAT
ORDER BY z.ID_ZESP, p.ETAT