Tech-ecke - Tasmota Datenlogger

<html lang="de">
<head>
<title>StromLogger</title>
<link rel="stylesheet" type="text/css" href="styles/style.css">

</head>
<body>
<?php
// Zugangsdaten geg. anpassen
$con=mysqli_connect("localhost","Tasmota","Tasmota","StromLogger");

date_default_timezone_set('Europe/Luxembourg');

// Daten sammeln
$jahr=2000+date('y');
$monat = date('m');
$tag = date('j');
$stunde = date('H');
$minute = date('i');
$sekunde = date('s');

$date = $jahr;
$date .= "-";
$date .= $monat;
$date .= "-";
$date .= $tag;

$time = $stunde;
$time .= ":";
$time .= $minute;
$time .= ":";
$time .= $sekunde;

$in = $_GET['a'];
$out = $_GET['b'];
$cur = $_GET['c'];
$sql = "INSERT INTO Verbrauch(Datum,Uhrzeit,Bezug,Einspeisen,Watt) VALUES('$date','$time','$in','$out','$cur')";
if (!mysqli_query($con,$sql))
{
die('Fehler: ' . mysqli_error($con));
}
else
echo "OK";

mysqli_close($con);
?>

</body>
</html>