Untitled

<html>
<head>
    <title>Log In | Subject Choice</title>
</head>
<body>
<h1>Log In Below:</h1>
<p>If you don't have an account <a href="index.php">create one here</a>.</p>

<form method="POST" action="login.php">
User <br><input type="text" name="username" size="40"><br>
Password <br><input type="password" name="password" size="40"><br>
<input id="button" type="submit" name="submit" value="Log-In"> </form>

<?php
    if(!empty($_POST['username'])) //only query the database once username has been submitted

    {
        $mysqli = new mysqli($HOST, $USER, $PASS, $NAME);
        if ($mysqli->connect_errno) {
            echo "<p>MySQL error no {$mysqli->connect_errno} : {$mysqli->connect_error}</p>";
            exit();
        }

$username = $_POST['username'];
$password = $_POST['password'];

$sql = "SELECT * from userdata WHERE username = '{$username}' AND password = '{$password}' LIMIT 1";

$result = $mysqli->query($sql);
    if ($result->num_rows == 0) {
        echo "<p>Incorrect Username/Password.</p>";
} else {
echo "<p>Logged in successfully</p>


$sql = "SELECT subject1, subject2, subject3 FROM userdata WHERE username = '{$username}'";

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "<b>First Subject Choice: </b>" . $row["subject1"]. "<br><b>Second Subject Choice: </b>" . $row["subject2"]. "<br><b>Third Subject Choice </b>" . $row["subject3"]. "<br>";
}

} else {
echo "0 results";
}

}
}
?>
</body>
</html>