clear variable from letters etc

[__berfuzz]

I have man a script that clears - letters etc from variables. It seems to work:

$num = "t23-4t23 4";
echo "$num";
$num = (int)preg_replace('/\P{Nd}/u', '', $num);
$num = str_replace(array("-", " "), "", $num);
echo "<br />$num";

echos:
t23-4t23 4
234234

However, when I try to use this in a sql update it doesn't work.

	if (isset($_POST['vara']))
	{
		$vara = explode(' - ', $_POST['vara']);
		$kontroll = 0;
		      $num = $_POST['num'];                  //problem here, or elsewhere???
		      $num = str_replace(array("-", " "), "", $num);
             $num = (int)preg_replace('/\P{Nd}/u', '', $num);
		$klient = $vara[0];
		if (isset($_POST['port'])) { $port=' - '.$_POST['port'];}
		if (isset($_POST['music'])) { $music=' - '.$_POST['music'];}
		$produkt = $vara[1] . $port . $music;
		$time = time();
		if (empty($telenr) || empty($vara))
			{
				echo '<h2>Fyll i alla f&#228;lt!</h2>';
	 		}else{
			$query = "INSERT INTO resultat VALUES ('','$user','$team','$num','$klient','$produkt','$kontroll',NULL,'$time')";


		if (!mysql_query($query,$conn))
		{
			die('Error: ' . mysql_error());
 		}
	}
}

Edit: fixed missing perg_replace

[Kudose]

I don't see preg_replace in your second set of code.

Can you also explain how it doesn't work?

[__berfuzz]

When I run it in the sql update it doesn't work. If I try to put in t345 it doesn't clear out the t, like it does in the first script. I get MySQL error: Unknown column 't44' in 'where clause'

[cahva]

Im sorry but you havent given us the UPDATE sql. Theres only INSERT query in the script you gave us. But that error is quite clear and we can definetly spot the error if you give us the corresponding script that does the update.

[__berfuzz]

Well the problem seems to be the variable $num. And it is the insert i showed, just wrote update, my bad. Let's put it this way.
1. How do I clear a variable from letters?
Is there something wrong with

$num = (int)preg_replace('/\P{Nd}/u', '', $num);

Is it posible to add - and spacing ' ' in the preg_replace() i use?