如何让wordpress后台搜索只匹配搜索文章标题

add_filter( 'posts_search', 'ytkah_search_by_title', 10, 2 );
function ytkah_search_by_title( $search, $wp_query ) {
    if ( ! empty( $search ) && ! empty( $wp_query->query_vars['search_terms'] ) ) {
        global $wpdb;
        $q = $wp_query->query_vars;
        $n = ! empty( $q['exact'] ) ? '' : '%';
        $search = array();
        foreach ( ( array ) $q['search_terms'] as $term )
            $search[] = $wpdb->prepare( "$wpdb->posts.post_title LIKE %s", $n . $wpdb->esc_like( $term ) . $n );
        if ( ! is_user_logged_in() )
            $search[] = "$wpdb->posts.post_password = ''";
        $search = ' AND ' . implode( ' AND ', $search );
    }
    return $search;
}