Shopping cart not displaying products, intval? - php

Question

I am creating a PHP shopping cart linked to SQL database, from a tutorial i am following.
The code below SHOULD display all my products, however I believe that the
$id = intval($_GET['id']);
section is messing it up. The SKU's of the products are Varchar, not integers, so I am lead to believe that this is causing the problem with "intval". Is there another datatype I can insert that will display my products again?
<?php
if (isset($_GET['action']) && $_GET['action'] == "add")
{
$id = intval($_GET['id']);
if(isset($_SESSION['cart'][$id]))
{
$_SESSION['cart'][$id]['quantity']++;
}
else
{
$sql2 = "SELECT * FROM products WHERE SKU={$id}";
$query2 = mysql_query($sql2);
if(mysql_num_rows($query2) != 0)
{
$row2 = mysql_fetch_array($query2);
$_SESSION['cart'][$row2['SKU']] = array("quantity => 1, "price" => $row['price']);
}
else
{
$message = "This product id is invalid";
}
}
}
?>
<h2 class="message"><?php if(isset($message)){echo $message; ?></h2>
<h1>Product Page</h1>
<table>
<tr>
<th>Name</th>
<th>Description</th>
<th>Price</th>
<th>Action</th>
</tr>
<?php
$sql = "SELECT * FROM products ORDER BY SKU ASC";
$query = mysql_query($sql)or die(mysql_error());
while($row = mysql_fetch_assoc($query))
{
?>
<tr>
<td><?php echo $row['name']; ?></td>
<td><?php echo $row['Description']; ?></td>
<td><?php echo "£" . $row['price']; ?></td>
<td>Add to Cart</td>
</tr>
<?php
}
?>
</table>

Answer 1

You are missing an ending quote here:
$_SESSION['cart'][$row2['SKU']] = array("quantity" => 1, "price" => $row['price']);
You're also missing a } sign
<h2 class="message"><?php if(isset($message)){echo $message; } ?> </h2>

Answer 2

Check the docs for intval() and you'll see that this method returns 0 when the variable isn't an integer.
if you're looking to search for this, you can just change the line to:
$id = $_GET['id'];
to get the variable as a string
However there are two things to bear in mind with this:
This is liable to lead to sql injection vulnerabilities if not treated properly in your code
The mysql_ functions are deprecated, and shouldn't be used in new code... there're a number of good tutorials and debates on the matter... use PDO or mysqli