Random post on front page

I’m trying to display one random post on the front page.

I put this code before The Loop and it works well, except it doesn’t display comments or split posts with More tag.

<?php
$rand_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE post_status = 'publish' ORDER BY RAND() LIMIT 1");
query_posts("p=$rand_id");
?>

I also tried this code, but it didn’t work at all. Maybe I just didn’t implement it correctly.

<?php
global $wpdb;
$numposts = 1;

$rand_posts = $wpdb->get_results("SELECT * FROM $wpdb->posts WHERE post_status = 'publish' ORDER BY RAND() LIMIT $numposts");
foreach($rand_posts as $post) :
setup_postdata($post);
?>

...

<?php endforeach; ?>

Can someone please tell me how to get either one of these working correctly?

Thanks