php POST to mySQL

<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db"); //remember to put the server address here
// Check connection
if (mysqli_connect_errno()) {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$result = mysqli_query($con,"SELECT * FROM data");
while($row = mysqli_fetch_array($result)) {
  $IDnr = $row['ID']+1;
}
$IDnr = mysql_real_escape_string($IDnr);
$timestamp = mysql_real_escape_string(date("Y-m-d H:i:s"));
$MeterID = mysql_real_escape_string($_GET["MeterID"]);
$V1 = mysql_real_escape_string($_GET["V1"]);
$A1 = mysql_real_escape_string($_GET["A1"]);
$W1 = mysql_real_escape_string($_GET["W1"]);
$V2 = mysql_real_escape_string($_GET["V2"]);
$A2 = mysql_real_escape_string($_GET["A2"]);
$W2 = mysql_real_escape_string($_GET["W2"]);
$V3 = mysql_real_escape_string($_GET["V3"]);
$A3 = mysql_real_escape_string($_GET["A3"]);
$W3 = mysql_real_escape_string($_GET["W3"]);
$AN = mysql_real_escape_string($_GET["AN"]);

mysqli_query($con,"INSERT INTO data (ID, UTC, MeterID, V1, A1, W1, V2, A2, W2, V3, A3, W3, AN)
VALUES ('$IDnr', '$timestamp', '$MeterID', '$V1', '$A1', '$W1', '$V2', '$A2', '$W2', '$V3', '$A3', '$W3', '$AN')");

$result = mysqli_query($con,"SELECT * FROM data");
while($row = mysqli_fetch_array($result)) {
  $IDnr = $row['ID'];
  echo $IDnr." ".$row['MeterID']." ".$row['UTC']."<br>";
}

mysqli_close($con);
?>