Question

这可能吗？桌子上的一列中有两列？

$this->db->select('header.*,customer.*,destination.location');
$this->db->from(self::WAYBILL_HEADER_TABLE. " as header");
$this->db->join(self::CUSTOMER_TABLE." as customer","header.consignee = customer.id");
$this->db->join(self::WAYBILLDESTINATION_TABLE. " as destination","header.destination_from = destination.id",'INNER');

$this->db->join(self::WAYBILLDESTINATION_TABLE. " as destinations","header.destination_to = destinations.id",'INNER');
$this->db->where('header.waybilldate <=',$date_to);
$this->db->where('header.waybilldate >=',$date_from);
$this->db->order_by('header.waybillno','DESC');
$query = $this->db->get()->result();
return $query;

Answer 1

试试这个

 $this->db->join('t2', 't1.x = t2.c', 'left');

Answer 2

您的问题不明确，但要将两列合并为一列，您可以在select语句中使用CONCAT函数，如下所示

$this->db->select('table_name.column1, CONCAT(table_name.column2, ' ', table_name.column3) as table_name.twoInOne');

这只是一个如何使用concat功能的想法。此外，对于群组联合检查this answer。

Answer 3

尝试：

$ this-＆gt; db-＆gt; query（“SELECT CONCAT（column1，''，column2）FROM employee_tbl”）;

http://www.tutorialspoint.com/mysql/mysql-concat-function.htm

Answer 4

我建议在同一张表中联接两个或更多列：

    $this->db->select("*");
    $this->db->from("follows");
    $this->db->join('users table1','table1.user_id=follows.following_id','left');
    $this->db->join('users table2','table2.user_id=follows.follower_id','left');
    $this->db->where("table1.is_active",1);
    $this->db->where("table2.is_active",1);
    $res=$this->db->get();
    return $res->result();

在一列codeigniter中加入两列

4 个答案: