live viewer count

<?php
if(!session_id()) {
    session_start();
}
$servername = "localhost";
$dbusername = "root";
$dbpassword = "blackpeoplemeet.com";
$dbname = "stream";
$conn = new mysqli($servername, $dbusername, $dbpassword, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$ip = $_SERVER['REMOTE_ADDR'];
$datetime = date('Y-m-d H:i:s');
$username = '';
$session_id = session_id();
if (isset($_COOKIE['Login'])) {
    parse_str($_COOKIE['Login'], $login);
    $username = $login['Login-user'];
}

$sql = "SELECT ip, username FROM viewers WHERE ip = '$ip' AND session_id = '$session_id'";
$result = mysqli_query($conn, $sql);
if (!empty($result)) {
    $row = mysqli_fetch_array($result);
}
if (!empty($row)) {
    $sql = "UPDATE viewers SET datetime = '$datetime' WHERE ip = '$ip'";
} else {
    $sql = "INSERT INTO viewers (session_id, ip, username, datetime) VALUES ('$session_id', '$ip', '$username', '$datetime')";
}
mysqli_query($conn, $sql);

$sql = "SELECT ip, username, datetime FROM viewers";
$result = mysqli_query($conn, $sql);
$viewers = 0;
$anonviewers = 0;
if (!empty($result)) {
    while ($row = mysqli_fetch_assoc($result)) {
        $time = strtotime($row['datetime']);
        if (time() - $time > 60) {
            $sql = "DELETE FROM viewers WHERE ip='$row[ip]'";
            mysqli_query($conn, $sql);
        }
        else {
            if (!empty($row['username'])) {
            $users[] = $row['username'];
            }
            else {
                $anonviewers++;
            }
            $viewers++;
        }
    }
}

if ($viewers != 0) {
    $out = "<h2>Total Viewers: ". $viewers ."</h2>";
}
else {
    $out = "<h2>you broke it</h2>";
}
if (isset($users)) {
    foreach ($users as $i) {
        $out .= "<p>". $i ."</p>";
    }
}
if ($anonviewers != 0) {
    $out .= "<p>Anonymous Viewers: ". $anonviewers ."</p>";
}

echo $out;

?>