$result = $query->select($fields)
            ->from('dav_shares', 's')
            ->join('s', 'calendars', 'a', $query->expr()->eq('s.resourceid', 'a.id'))
            ->where($query->expr()->in('s.access', $query->createNamedParameter(self::ACCESS_PUBLIC)))
            ->andWhere($query->expr()->eq('s.type', $query->createNamedParameter('calendar')))