Custom post meta

Hi
I need help. I would like to retrieve the posts by meta query and sort them by value, no matter whether the meta post exists or not.

$args=array(
			'posts_per_page' => -1,
			'meta_key' => 'mymeta',
			'meta_type' => 'NUMERIC',
			'orderby' => 'meta_value',
			'order' => 'ASC',
			'meta_query' => array(
				'relation' => 'OR',
				array(
					'key' => 'mymeta',
					'compare' => 'NOT EXISTS'
				)
			)
		);
		$query = new WP_Query($args);

If there is no entry in postmeta then does not show any entries