function category_has_children

Hi

So I got the function thats checking if the current category has any children. And it works great on archive.php template. But I want to do exact same thing on single.php but it doesnt work… If You know what should I change in the code belowe to make it work also on single.php I would be delighted:

function category_has_children() {
global $wpdb;
$term = get_queried_object();
$category_children_check = $wpdb->get_results(" SELECT * FROM wp_term_taxonomy WHERE parent = '$term->term_id' ");
     if ($category_children_check) {
          return true;
     } else {
          return false;
     }
}