SELECT  e.Id_egzaminator , e.Imie, e.Nazwisko, COUNT(*) AS "Liczba egzaminow"
FROM Egzaminatorzy e
INNER JOIN Egzaminy egz
ON e.Id_egzaminator = egz.Id_egzaminator
GROUP BY e.Id_egzaminator, e.Imie, e.Nazwisko
HAVING COUNT(*) = (SELECT MAX(COUNT(*)) FROM Egzaminy e
GROUP BY e.Id_egzaminator
)