SELECT DISTINCT c.name
FROM company.c
INNER JOIN member m
ON m.company_name=c.name
LEFT OUTER JOIN participation p
ON m.first_name=p.first_name AND m.last_name=p.last_name
LEFT OUTER JOIN event e
ON e.event_date=p.event_event_date AND e.name='some-event'
WHERE NOT e.name IS NULL;