php - 如何更改codeigniter中的mysql查询

Question

如何在 codeigniter 中更改此 mysql 查询？

此查询正在运行:

/$query = $this->db->query("SELECT * FROM user_registration WHERE Ins_ID=(SELECT Ins_ID FROM login WHERE User_Name='$User_Name')");

我想将其更改为评论下面的格式。谢谢。

 public function view($User_Name)
     {
         if($User_Name != NULL)
         {
            //$query = $this->db->query("SELECT * FROM user_registration WHERE Ins_ID=(SELECT Ins_ID FROM login WHERE User_Name='$User_Name')"); //edited

             $Ins_ID=$this->db->query("SELECT Ins_ID FROM login WHERE User_Name='$User_Name'");
             $this -> db -> select('*');
             $this -> db -> from('user_registration');
             $this -> db -> where('Ins_ID',$Ins_ID);
             $query = $this -> db -> get();

             return $query->row();
         }

     }

Answer 1

您需要连接表而不使用子查询

$this->db->select('r.*');
$this->db->from('user_registration r');
$this->db->join('login l','r.Ins_ID=l.Ins_ID')
$this->db-> where('l.User_Name',$User_Name);
$query =$this->db->get();

Active Record