prüfen ob eine seite unterseiten hat

<?php /* Creates a menu for pages beneath the level of the current page */
  if (is_page() and ($notfound != '1')) {
   $current_page = $post->ID;
   while($current_page) {
    $page_query = $wpdb->get_row("SELECT ID, post_title, post_status, post_parent FROM $wpdb->posts WHERE ID = '$current_page'");
    $current_page = $page_query->post_parent;
   }
   $parent_id = $page_query->ID;
   $parent_title = $page_query->post_title;


   if ($wpdb->get_results("SELECT * FROM $wpdb->posts WHERE post_parent = '$parent_id' AND post_status != 'attachment'")) { ?>


   <h2><?php echo $parent_title; ?> <?php _e('- mehr'); ?></h2>
    <ul>
     <?php wp_list_pages('sort_column=menu_order&title_li=&child_of='. $parent_id); ?>
    </ul>


    <?php if ($parent_id != $post->ID) { ?>
     <em><a href="<?php echo get_permalink($parent_id); ?>"><?php printf(__('Back to %s'), $parent_title ) ?></a></em>
    <?php } ?>


 <?php } } ?>


 <?php if (is_attachment()) { ?>
  <div class="sb-pagemenu">
   <a href="<?php echo get_permalink($post->post_parent); ?>" rev="attachment"><?php printf(__('Back to \'%s\''), get_the_title($post->post_parent) ) ?></a>
  </div>
<br/>
 <?php } ?>