問(wèn)題是什么？代碼：  $this->db->select('items.*, tags.name, users.user_name');  $this->db->from('items');  $this->db->join('tags', 'tag = tags.id');  $this->db->join('users', 'id_user = users.id');  $this->db->where('items', array('id' => $id));  $query = $this->db->get();    return $query->row_array();打印 ：錯(cuò)誤編號(hào)：1054“ where子句”中的未知列“ items”SELECT `items`.*, `tags`.`name`, `users`.`user_name` FROM `items` JOIN `tags` ON `tag` = `tags`.`id` JOIN `users` ON `id_user` = `users`.`id` WHERE `items` = Array文件名：C：/xampp/htdocs/system/database/DB_driver.php行號(hào)：691