<?php
require_once('connection.php');

session_start();
if(isset($_POST['username']) && isset($_POST['password'])){
    $username = $_POST['username'];
    $password = $_POST['password'];
    $query = $con->prepare("SELECT username, password FROM member WHERE username = '".$username."' && password = '".$password."'");
    $query->execute();
    while ($row = $query->fetch(PDO::FETCH_ASSOC)){
        if($username != $row['username']){
            echo "Username is not exist";
        }
        if($password != $row['password']){
            echo "Password is not valid";
        }
        if($password == $row['username'] && $username == $row['password']){
            $_SESSION['username'] = $username;
            $_SESSION['password'] = $password;
            header('location: index.php');
        }
    }
}
?>