使用mysql加入显示不符值

Question

我有一个查询加入3个表。

$this->db->select("a.user_id as id, a.plate_number as plate_number, a.current_lat as lat, a.current_lon as lon, a.created_on as created_on, a.updated_on as updated_on, a.available as available, a.location_id as location_id, b.user_name as name, b.user_email as email, b.user_phone as phone, c.name as location_name"); 
     $this->db->from('user_driver as a'); 
     $this->db->join('user as b', 'a.user_id = b.user_id'); 
     $this->db->join('vendor_location as c', 'a.location_id = c.location_id'); 
     $query = $this->db->get(); 
     $data['driver'] = $query->result_array(); 

user_driver表结构：

vendor_location表结构：

结果：

我想表明user_driver表的其余部分，即使有不匹配值为vendor_location表。 LocationName字段可填写NULL，而不是根本不显示任何内容。

我试过left outer和full outer但它不起作用。它给我留下了唯一一行显示。

Answer 1

具有u试过这样

$this->db->join('user as b', 'a.user_id = b.user_id', 'LEFT'); 
    $this->db->join('vendor_location as c', 'a.location_id = c.location_id', 'LEFT'); 

Answer 2

我想表明user_driver表的其余部分，即使有不匹配的价值vendor_location表。

为此，您应该使用LEFT JOIN。它允许您从左侧的表中获取行，即使右表中没有匹配时也是如此。

$this->db->select("a.user_id as id, a.plate_number as plate_number, a.current_lat as lat, a.current_lon as lon, a.created_on as created_on, a.updated_on as updated_on, a.available as available, a.location_id as location_id, b.user_name as name, b.user_email as email, b.user_phone as phone, c.name as location_name"); 
$this->db->from('user_driver as a'); 
$this->db->join('user as b', 'a.user_id = b.user_id'); 
$this->db->join('vendor_location as c', 'a.location_id = c.location_id', 'left');//modify this line 
$query = $this->db->get(); 
$data['driver'] = $query->result_array();