custom meta query sorting

sorting-meta-query

add_filter( 'pre_get_posts', 'sort_by_likes' );
function sort_by_likes( $query ) {
    if ($query->is_home() && $query->is_main_query() ) {
	$query->set( 'meta_query', array(array(
    		 'key' => '_recommended'
	)));
$query->set('meta_key', '_recommended');
$query->set('orderby', 'meta_value_num');
$query->set('order', 'DESC');
}}


OR

$query->set('meta_query', array(
    array(
       'key' => '_ai_price_int',
       'value' => array(0, 4000),
       'compare' => 'BETWEEN',
       'type' => 'NUMERIC'
    )
));
$query->set('meta_key', '_ai_price_int');
$query->set('orderby', 'meta_value_num');