change node__field_location  to your address field table name , column name also

     $query = \Drupal::database()->select('node__field_location', 'fa');
	$query->fields('fa', ['field_location_locality']);
	$query->condition('bundle', 'venture');
//	$query->condition('field_location_locality', '', 'like');
//        $query->condition('field_location_country_code', '');
        $query->distinct();
        $query->orderBy('field_location_locality');
	$courseRatings = $query->execute()->fetchAll(\PDO::FETCH_ASSOC);