Как сделать в Wordpress так чтобы поиск искал сначала по заголовкам, а если ничего не найдено, то по тексту статей?

function __search_by_title_only( $search, &$wp_query ){
  global $wpdb;
  if ( empty( $search ) ) return $search;

  $searchTitle = $wpdb->posts.post_title;
  $searchContent = $wpdb->posts.post_content;

  $q = $wp_query->query_vars;
  $n = ! empty( $q['exact'] ) ? '' : '%';
  $search =
  $searchand = '';

  foreach ( (array) $q['search_terms'] as $term ) {
    $term = esc_sql( like_escape( $term ) );
    $search .= "{$searchand}($searchTitle LIKE '{$n}{$term}{$n}')";
    $searchand = ' AND ';
    $search .= "{$searchand}($searchContent LIKE '{$n}{$term}{$n}')";
  }

  if ( ! empty( $search ) ) {
    $search = " AND ({$search}) ";
  if ( ! is_user_logged_in() )
    $search .= " AND ($wpdb->posts.post_password = '') ";
  }
  return $search;
}
add_filter( 'posts_search', '__search_by_title_only', 500, 2 );