php - I am making a user authentication page using CodeIgniter -

the problem query not retrieving correct value database rather not retrieving value. whenever try print variable holds result, blank. attaching part of code

this code in model

$db = new pdo('mysql:host=localhost;dbname=login;charset=utf8', 'root', 'learningit');     $db->setattribute(pdo::attr_errmode, pdo::errmode_exception);     $stmt = $db->prepare("select id members userid='$username' , password='$password'");       $stmt->execute();       $var=$stmt->fetch(pdo::fetch_assoc);      foreach ((array)$var $row) {     print_r($row);     return $row; 

& controller part

public function check()     {          $this->load->model('test_model');          $result=$this->test_model->data_check();          if($result[0]==1)         {           $this->call();         }         else if($result[0]==2)         {             $this->call1();         }         else if($result[0]==3)         {             $this->call2();         }         else         {                echo "invalid id/password";         }        } 

you might missing $username , $password declaration in model

$username = $this->input->post('username'); // change depends in input  $password = $this->input->post('password'); // change depends in input