加入3个mysql表php codeigniter

Question

我有以下3种类型的表，最后我需要获取属于users表的shop_admin和shop_coadmin电子邮件地址。

table-1-shop
-------------------------------
shop_id | shop_name | shop_admin(foreignkey user_id) | shop_coadmin(foreignkey user_id)

table-2-Users
-------------------------------
user_id |  user_name |  user_email

table-3-orders
--------------------------------
order_id | shop_id    

现在，我的要求是从用户表中获取shop_admin和shop_coadmin电子邮件ID，

订单包含shop_id ，使用shop_id它将搜索admin和coadmin id ，并需要在用户中搜索user_email ，

我尝试使用以下代码，但无法收到电子邮件

public function getAllCart($user_id,$paging, $ordering, $searching )
{
    $this->db->select('part_number, part_description, order_quantity, order_id, B.user_firstname, B.user_lastname, B.user_email, A.shop_name,
     A.shop_admin AS shop_admin');
    $this->db->from('li_orders');
    $paging;
    $ordering;
    $searching;

    $this->db->where('order_status', 'Cart');
    $this->db->join('li_parts', 'li_parts.part_id = li_orders.part_id','LEFT');
    $this->db->join('li_shop AS A', 'A.shop_id = li_orders.shop_id','LEFT');
    $this->db->join('li_users AS B', 'B.user_id = A.shop_admin','LEFT');
    $this->db->where('li_orders.user_id', $user_id);
    return $this->db->get()->result_array();
}

我该怎么办？

Answer 1

如果您的问题是仅收到具有上述代码的shop_admin电子邮件，则需要将具有另一个别名的li_users表添加到查询中，并将其加入li_shop.coadmin字段。 显然，您需要使用新别名添加表中的字段，并使用字段别名标记哪些用户详细信息用于管理员，哪些用户详细信息用于管理员。

...
$this->db->select('part_number, part_description, order_quantity, order_id, B.user_firstname as adminfirstname, B.user_lastname as adminlastname, B.user_email as adminemail, C.user_firstname as coadminfirstname, C.user_lastname as coadminlastname, C.user_email as coadminemail, A.shop_name,
 A.shop_admin AS shop_admin');
...
$this->db->join('li_users AS B', 'B.user_id = A.shop_admin','LEFT');
$this->db->join('li_users AS C', 'C.user_id = A.shop_coadmin','LEFT');
...

下次描述代码中使用的表结构时，请使用相同的表名和字段名。