query.php

$args = array(
	'offset' => $offset,
	'posts_per_page'=> $display_count,
	'paged'	=> $paged,
	'post_type' => 'resume',
	'meta_key' => 'ratings_average',
	'orderby' => 'meta_value_num',
	'order' => 'DESC',
	'meta_query' => array(
		'relation'=> 'AND',
		array(
			'key' => 'rating_average',
			'operator' => 'NOT EXISTS'
		),
		array(
			'key' => 'rating_average',
			'operator' => 'EXISTS'
		)
	)
);