//initialise attempt variable
$attempt = 1;

$attemptsQuery =
	"SELECT studentnumber, MAX(attempt)
		FROM attempts
		GROUP BY studentnumber";

$insertQuery =
	"INSERT INTO attempts VALUES (
		$date, $firstname, $lastname, $student, $attempt, $quizresult
	)";

$attemptsResult = mysqli_query($conn, $attemptsQuery);

if (mysqli_num_rows($attemptsResult)) == 0) {
	mysqli_query($conn, $insertQuery);
	echo "<a href=\"quiz.php\"> Click here to resit </a>";
} else {
	while ($maxAttempt = mysqli_fetch_assoc($attemptResult)) {

		if (($maxAttempt["studentnumber"] == $student) && ($maxAttempt["MAX(attempt)"] < 2)) {
			$attempt = $maxAttempt["MAX(attempt)"] + 1;
			mysqli_query($conn, $insertQuery);
			echo "<a href=\"quiz.php\"> Click here to resit </a>";
			break;
		} else if (($maxAttempt["studentnumber"] == $student) && ($maxAttempt["MAX(attempt)"] >= 2)) {
			echo "<p> You have run out of attempts </p>";
			break;
		}
	}
}