сортировка по рейтингу, комментариям

<?php
$order = "&orderby=cost&order=DESC";
$s2 = ' selected="selected"';
if ($_POST['select'] == 'title') { $order = "&orderby=title&order=ASC"; $s1 = ' selected="selected"'; $s2 = ''; }
if ($_POST['select'] == 'newest') { $order = "&orderby=cost&order=DESC"; $s2 = ' selected="selected"'; }
if ($_POST['select'] == 'oldest') { $order = "&orderby=cost&order=ASC"; $s3 = ' selected="selected"'; $s2 = ''; }
if ($_POST ['select']== 'rating') { $order = "'&r_sortby=highest_rated&r_orderby=desc"; $s5 = ' selected="selected"'; $s4 = ''; }
if ($_POST ['select']== 'komment') { $order = "'showposts&orderby=comment_count"; $s6 = ' selected="selected"'; $s5 = ''; }
?>

<form method="post" id="order" class="ordering-wrapper">
<?php _e('Сортировать', 'article-directory'); ?>:
<select name="select" onchange='this.form.submit()'>
<option value="title"<?=$s1?>><?php _e('По названию', 'article-directory'); ?></option>
<option value="newest"<?=$s2?>><?php _e('Новые вначале', 'article-directory'); ?></option>
<option value="oldest"<?=$s3?>><?php _e('Старые вначале', 'article-directory'); ?></option>
<option value="rating"<?=$s5?>>По рейтингу</option>
<option value="komment"<?=$s6?>>По комментариям</option>
</select>
</form>

<?php $posts = query_posts($query_string . "&" . $order); ?>