大家好，我创建了一个登录从它的完美工作，所以在同一时间，我试图获得用户名和密码，我输入的id，有人能告诉我怎么做。注意：我不太擅长php。谢谢您

<?php
   include("login.php");
   session_start();
   $notexist="";

   if($_SERVER["REQUEST_METHOD"] == "POST") {
      // username and password sent from form 

      $myusername = mysqli_real_escape_string($db,$_POST['email']);
      $mypassword = mysqli_real_escape_string($db,$_POST['password']); 
     $id;

      $sql = "SELECT ID FROM newdata WHERE  names = '$myusername' and password= '$mypassword' ";

      $result = mysqli_query($db,$sql);
      $row = mysqli_fetch_array($result,MYSQLI_ASSOC);

      $count = mysqli_num_rows($result);

      // If result matched $myusername and $mypassword, table row must be 1 row

      if($count == 1) {

        $notexist="";
        echo "yes";

        echo $myusername;
       $url = "test.php?username=".$myusername;

       $_SESSION['favcolor'] = 'green';
       exit();
      }else {
         $notexist="wrong username and password";
         echo  $notexist;
      }
   }
?>