<?php
/* Start non-duplicates */
function post_strip($where) {
	global $myPosts, $wpdb;
	$where .= " AND $wpdb->posts.ID not in($myPosts) "; 
	return $where;
}
?>
<?php 
global $myPosts;
$myPosts = '';
?>
<div>
<?php
$my_query = new WP_Query();
$my_query->query('showposts=5');
if ($my_query->have_posts()) : while ($my_query->have_posts()) : $my_query->the_post(); ?>
<?php $myPosts .= $post->ID . ","; ?>
<div><?php the_title(); ?></div>
<!-- Post Stuff -->
<?php endwhile; endif; ?>
</div>
<?php $myPosts .= "0" ?>
<?php add_filter('posts_where', 'post_strip'); ?>
<div><br/>
<?php //$my_query = new WP_Query('category_name=Life&showposts=15');
$my_query = new WP_Query('showposts=5');
while ($my_query->have_posts()) : $my_query->the_post();?> 
<div><?php the_title(); ?></div>
  
<!-- Post Stuff -->

<?php endwhile; ?>
</div>
<?php remove_filter('posts_where', 'post_strip'); ?>
<?php /* End non-duplicates  */ ?>

http://w3updates.com/wordpress-tips-and-tricks-avoid-duplicate-posts/

Wordpress Tips and Tricks : Avoid Duplicate Posts

wordpress

PHP