$sql = "SELECT * FROM event_topic WHERE time BETWEEN '$time' AND '$etime' AND ('" 
  . join( $verkn ,@veranstalter) . "') OR ('" . join( $verkn ,@veranstaltungsort) . "') OR ('" 
  . join( $verkn ,@location) . "') OR ('" . join( $verkn ,@titel) . "') OR ('" 
  . join( $verkn ,@beschreibung) . "') ORDER BY time";