SELECT a.generic_event_id, g.name Event_Name, COUNT(a.generic_event_id) MaxEventOcurance, p.first_name||' '||p.last_name Person_Names, v.vehicle_id, v.numberplate||v.company_nr, gg.first_name||' '||gg.last_name GUI_USER_Names, u.vehicle_id object_id, u.numberplate||u.company_nr
FROM attach_doc a
LEFT OUTER JOIN GENERIC_EVENT g ON (a.generic_event_id=g.generic_event_id)
LEFT OUTER JOIN person p ON (a.person_id=p.person_id)
LEFT OUTER JOIN vehicle v ON (a.VEHICLE_ID=v.VEHICLE_ID)
LEFT OUTER JOIN vehicle u ON (a.object_id=u.VEHICLE_ID)
LEFT OUTER JOIN gui_users gg ON (a.gui_user_id=gg.gui_user_id)
GROUP BY a.generic_event_id, g.name, p.first_name||' '||p.last_name, v.vehicle_id, v.numberplate||v.company_nr, gg.first_name||' '||gg.last_name, u.vehicle_id, u.numberplate||u.company_nr
HAVING COUNT(a.generic_event_id)=(SELECT MAX(COUNT(a.generic_event_id)) maxa
FROM attach_doc a
GROUP BY a.generic_event_id);