Filter to avoid duplicate content

<!--?php
require_once("wp-load.php");
query_posts("post_status=draft&#038;orderby=date&#038;order=DESC");
global $table_prefix;
// The Loop
while ( have_posts() ) : the_post();
	//Process each draft post here
	global $post;
	if ($post--->post_status == "draft") {
		$current_ID = get_the_ID();
		$current_title = $post->post_title;
		$current_content = $post->post_content;
		$current_email = get_post_meta($current_ID, 'email', true);
		$current_postname = $post->post_name;
		echo "Processing draft post: ".$current_ID." - ";
		the_title();
		echo "...";
		// Create a new instance
		// Search for published posts with same content and same email
		$sql = "select * from ".$table_prefix."posts as posts LEFT JOIN ".$table_prefix."postmeta as postmeta ON posts.ID=postmeta.post_id where post_content = '".$current_content."' and post_status = 'publish' and meta_key='email' and meta_value='".$current_email."'";
		$result = mysql_query($sql);
		$deletion = false;
		while ($row = mysql_fetch_array($result)) {
			echo " found a similar post content and email custom field. Deleting ...";
			wp_delete_post( $current_ID );
			echo " done";
			$deletion = true;
			break;
		}
		if (!$deletion) {
			echo " not found any similar one. Publishing ...";
			if ($current_postname == "") {
				$current_postname = sanitize_title($current_title);
			}
			$postUpdate = array();
			$postUpdate['ID'] = $current_ID;
			$postUpdate['post_name'] = $current_postname;
			wp_update_post( $postUpdate );
			wp_publish_post( $current_ID );
			echo " done";
		}
		mysql_free_result($result);
 
	}
	echo "";
	ob_flush();
	flush();
endwhile;
 
// Reset Query
wp_reset_query();