Untitled

$exists = false;
            $user = $_POST["username"];
            $pass = $_POST["password"];
            $cpass = $_POST["cpassword"];
            $db_check = "SELECT * FROM `users`.`userdata` WHERE `username` = $user";
            $result1 = $conn->query($db_check);
            if($result1->num_rows > 0){
                $exists = true;
            }