[RESOLVED] updating records in db error

[dr_aybyd]

Hi, i am new in php

Whats wrong with my codes?
My server is using PHP Version 5.2.11

<?php
$con = mysql_connect("localhost","username","password");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("my_database", $con);
mysql_query("UPDATE my_table SET 
machinetime = '$_POST[strDate]',
server = '$_POST[strServer]',
name = '$_POST[struser]',
imei = '$_POST[strImei]',
model = '$_POST[strModel]',
price = '$_POST[strPrice]',
refnum = '$_POST[strRef]'
WHERE PID = '$_POST[processID]'");
if (!mysql_query($sql,$con))
  {
  die('Error: ' . mysql_error());
  }
echo "Record Updated";
mysql_close($con)
?>

When i click submit in my Form

It always throw me an error "Error: Query was empty"