Popular posts (by comment count) in Wordpress with no plug-in

1.php

<?php $pop = $wpdb->get_results("SELECT * FROM {$wpdb->prefix}posts WHERE post_type='post' AND post_status='publish' ORDER BY comment_count DESC LIMIT 10"); ?>

<?php foreach($pop as $post) : ?>
<?php get_template_part( 'content', get_post_format() ); ?>
<?php endforeach; ?>

2.php

<?php foreach($pop as $post) : ?>
<ul>
<li> <?php the_title(); ?> </li>
</ul>
<?php endforeach; ?>