<?php

include 'db_connect.php';

$username = $_POST["username"];
$pass = $_POST["pass"];

$sql = "SELECT * FROM users WHERE username='$username' AND pass='$pass'";
$result = $conn->query($sql);

if(!$row = $result->fetch_assoc()) {
    echo "Your login or password is incorrect";
} else {
    echo "You are logged";
}