/**
  * ルートフォルダ取得
  *
  * @param $community_id
  */
 static function select_root_folder_row($community_id)
 {
     $sql_where = "folder.community_id = " . $community_id;
     $sql_where .= " AND folder.parent_folder_id IS NULL ";
     $row_array = ACSFolderModel::select_common_folder_row_array($sql_where);
     return $row_array[0];
 }