protected static function get_fields()
 {
     return self::select_fields() . ", " . Event::select_fields() . ", " . Group::select_fields();
 }
 protected static function get_fields()
 {
     return implode(', ', array(self::select_fields(), Event::select_fields(), SeatingGroup::select_fields()));
 }
 protected static function get_fields()
 {
     return self::select_fields() . ", " . User::select_fields() . ", " . EventTicket::select_fields() . ", " . Event::select_fields() . ", " . EventSeat::select_fields() . ", " . User::select_fields('managers');
 }
 protected static function get_fields()
 {
     return implode(', ', array(self::select_fields(), User::select_fields(), User::select_fields('referer'), EventSignup::select_fields(), EventTicket::select_fields(), Event::select_fields()));
 }
 protected static function get_fields()
 {
     return self::select_fields() . ", " . Event::select_fields() . ", " . SeatingPlan::select_fields();
 }