小站成航先森文章阅读统计使用的是在WordPress大学中看到的代码实现的：WordPress非插件添加文章浏览次数统计功能
文章中写了统计、显示阅读次数的代码，以及获取阅读量最多的代码。
我想要修改获取阅读量最多的代码，使其能够实现类似“获取最近30天阅读量最多的文章”效果，有没有大神能帮忙实现，或者有大神已经实现过？小弟已经折腾的精疲力尽了。
主要代码如下：

/// get_most_viewed_format
/// 函数作用：取得阅读最多的文章
function get_most_viewed_format($mode = '', $limit = 10, $show_date = 0, $term_id = 0, $beforetitle= '(', $aftertitle = ')', $beforedate= '(', $afterdate = ')', $beforecount= '(', $aftercount = ')') {
  global $wpdb, $post;
  $output = '';
  $mode = ($mode == '') ? 'post' : $mode;
  $type_sql = ($mode != 'both') ? "AND post_type='$mode'" : '';
  $term_sql = (is_array($term_id)) ? "AND $wpdb->term_taxonomy.term_id IN (" . join(',', $term_id) . ')' : ($term_id != 0 ? "AND $wpdb->term_taxonomy.term_id = $term_id" : '');
  $term_sql.= $term_id ? " AND $wpdb->term_taxonomy.taxonomy != 'link_category'" : '';
  $inr_join = $term_id ? "INNER JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) INNER JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)" : '';
 
  // database query
  $most_viewed = $wpdb->get_results("SELECT ID, post_date, post_title, (meta_value+0) AS views FROM $wpdb->posts LEFT JOIN $wpdb->postmeta ON ($wpdb->posts.ID = $wpdb->postmeta.post_id) $inr_join WHERE post_status = 'publish' AND post_password = '' $term_sql $type_sql AND meta_key = 'views' GROUP BY ID ORDER BY views DESC LIMIT $limit");
  if ($most_viewed) {
   foreach ($most_viewed as $viewed) {
    $post_ID    = $viewed->ID;
    $post_views = number_format($viewed->views);
    $post_title = esc_attr($viewed->post_title);
    $get_permalink = esc_attr(get_permalink($post_ID));
    $output .= "
$beforetitle$post_title$aftertitle";
    if ($show_date) {
      $posted = date(get_option('date_format'), strtotime($viewed->post_date));
      $output .= "$beforedate $posted $afterdate";
    }
    $output .= "$beforecount $post_views $aftercount
";
   }
  } else {
   $output = "
N/A
n";
  }
  echo $output;
}