stressed over querys

[include_me]

Hello,

Im trying to make a query which when called calls the specific data from DB and displays on product page..

the query works like this:
producttest.php?model=(modelnumberhere)

it works when i put:
producttest.php?model=1100

BUT

when i put:
producttest.php?model=n90

it comes up with: Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource.

Is there something im doing wrong with my query? im using this query to select the data from DB:

<?php
if ($_GET['model']) {
	require('conn.php');
	$q = "SELECT * FROM products WHERE model = {$_GET['model']}";
	$r = mysql_query ($q);
	$row = mysql_fetch_array($r, MYSQL_ASSOC);
	mysql_close();
} else {
	header ("Location: [url]http://[/url]" .$_SERVER['HTTP_HOST'] . dirname($_SERVER['PHP_SELF']) ."/index.php");
}
?>

Please somebody help i have been doing this all day and im ready to boot my computer screen across the office..

Thanks
Chris

[MikeSnead]

Wrap the model in single quotes like:

$q = "SELECT * FROM products WHERE model = '{$_GET['model']}'";

If you put anything other than an integer without the single quotes bad things happen.