Meta Key by Query
$autore = get_the_ID(); $args = array( 'post_type' => 'libri', 'post_status' => 'publish', 'order' => 'DESC', 'orderby' => 'date', 'ignore_sticky_posts' => true, 'posts_per_page' => -1, 'meta_query' => array( array( 'key' => 'autori', 'value' => '"' . $autore . '"', 'compare' => 'LIKE' )) ); $libri = new WP_Query( $args );