In WordPress, how can I only show something in a page has children pages?

Question

I have this code, which automatically generates a vertical navigation based on the current pages children or sibling pages. How can I modify this, so that if there are no children or sibling pages, the <ul> doesn't show up? I'm pretty new to both PHP and WordPress, so sorry if this is a stupid question.

<ul>
    <?php
        global $wp_query;
        if( empty($wp_query->post->post_parent) ) {
            $parent = $wp_query->post->ID;
        } else {
            $parent = $wp_query->post->post_parent;
        }
        wp_list_pages ("&title_li=&child_of=$parent");
    ?>
</ul>

Answer 1

You could try

<?php

global $wp_query;

if( empty($wp_query->post->post_parent) ) {
    $parent = $wp_query->post->ID;
} else {
    $parent = $wp_query->post->post_parent;
}

$children = get_pages('child_of='.$parent);

if( count( $children ) > 0 ) { ?>
    <ul>
       <?php wp_list_pages ("&title_li=&child_of=$parent"); ?>
    </ul>
<?php }