'where子句'中的未知列'项'（codeigniter）

What is the problem؟

code:

  $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();

print :

Error Number: 1054

Unknown column 'items' in 'where clause'

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

Filename: C:/xampp/htdocs/system/database/DB_driver.php

Line Number: 691

instead of this

$this->db->where('items', array('id' => $id));

try this

$this->db->where('items.id', $id);

There are no column name items , the items is a table.