php issues adding product to shopping cart - php

Question

I'm having issues adding products to my shopping cart. In order to read it easier I'm only posing the php code. I'm not worried about security issues at this point, just looking to correct the issue with the product not showing up in the cart on the page view_cart.php . Can anyone see what I'm missing here? Also, the session is started on another page prior to them reaching this point.
<?php # add_cart.php
// This page adds beers to the shopping cart.
if (isset($_GET['beer_id'])) { // Check for a beer ID.
$beer_id = $_GET['beer_id'];
// Check if the cart already contains one of these beers;
// If so, increment the quantity:
if (isset($_SESSION['cart'][$beer_id])) {
echo '<p> same beer </p>';
$_SESSION['cart'][$beer_id]['quantity']++; // Add another.
// Display a message:
echo '<p> This brew was already in your cart so we added another to your shopping cart. </p>';
} else { // New product to the cart.
require ('mysqli_connect.php'); // Connect to the database.
$q = "SELECT price FROM beer WHERE beer_id='" . $beer_id . "'";
$r = mysqli_query ($dbc, $q);
if (mysqli_num_rows($r) == 1) { // Valid beer_ID.
// Fetch the information.
list($price) = mysqli_fetch_array ($r, MYSQLI_NUM);
// Add to the cart:
$_SESSION['cart'] = array('quantity' => 1, 'price' => $price);
echo $_SESSION['cart'][$beer_id][$r];
// Display a message:
echo '<p>' . $beer_id . 'has been added to your shopping cart.<br/>Go to Cart or Keep Shopping</p>';
} else { // Not a valid beer_ID.
echo '<div align="center">This page has been accessed in error!</div>';
}
mysqli_close($dbc);
}
}// End of isset conditional.
else { // No beer_ID.
echo '<div align="center">This page has been accessed in error!</div>';
}
?>
The page below is called from add_cart.php
<?php
# view_cart.php
// Check if the form has been submitted (to update the cart):
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
// Change any quantities:
foreach ($_POST['quantity'] as $k => $v) {
$beer_id = (int) $k;
$qty = (int) $v;
if ( $qty == 0 ) { // Delete.
unset ($_SESSION['cart'][$beer_id]);
} elseif ( $qty > 0 ) { // Change quantity.
$_SESSION['cart'][$beer_id]['quantity'] = $qty;
}
} // End of FOREACH.
} // End of SUBMITTED IF.
// Display the cart if it's not empty...
if (!empty($_SESSION['cart'])) {
// Retrieve information for beers in cart:
require ('mysqli_connect.php'); // Connect to the database.
$q = "SELECT beer_id, name, price FROM beer WHERE beer_id ='".$beer_id."'";
/*foreach ($_SESSION['cart'] as $beer_id => $value) {
$q .= $beer_id . ',';
}*/
$q = substr($q, 0, -1) . ') ORDER BY beer_id ASC';
$r = mysqli_query ($dbc, $q);
// Create a form and a table:
echo '<form action="view_cart.php" method="post">
<table border="0" width="90%" cellspacing="3" cellpadding="3" align="center">
<tr>
<td align="left" width="30%"><b>ID</b></td>
<td align="left" width="30%"><b>Name</b></td>
<td align="right" width="10%"><b>Price</b></td>
<td align="center" width="10%"><b>Qty</b></td>
<td align="right" width="10%"><b>Total Price</b></td>
</tr>
';
// Print each item...
$total = 0; // Total cost of the order.
while ($row = mysqli_fetch_array ($r, MYSQLI_ASSOC)) {
// Calculate the total and sub-totals.
$subtotal = $_SESSION['cart'][$row['beer_id']]['quantity'] * $_SESSION['cart'][$row['beer_id']]['price'];
$total += $subtotal;
// Print the row:
echo "\t<tr>
<td align=\"left\">{$row['name']}</td>
<td align=\"right\">\${$_SESSION['cart'][$row['beer_id']]['price']}</td>
<td align=\"center\"><input type=\"text\" size=\"3\" name=\"qty[{$row['beer_id']}]\" value=\"{$_SESSION['cart'][$row['beer_id']]['quantity']}\" /></td>
<td align=\"right\">$" . number_format ($subtotal, 2) . "</td>
</tr>\n";
} // End of the WHILE loop.
mysqli_close($dbc); // Close the db connection.
// Print the total, close the table, and the form:
echo '<tr>
<td colspan="4" align="right"><b>Total:</b></td>
<td align="right">$' . number_format ($total, 2) . '</td>
</tr>
</table>
<div align="center"><input type="submit" name="submit" value="Update My Cart" /></div>
</form><p align="center">Enter a quantity of 0 to remove an item.
<br /><br />Checkout</p>';
} else {
echo '<form action="view_cart.php" method="post">
<table border="0" width="90%" cellspacing="3" cellpadding="3" align="center">
<tr>
<td align="left" width="10%"><b>ID</b></td>
<td align="left" width="30%"><b>Name</b></td>
<td align="right" width="30%"><b>Price</b></td>
<td align="center" width="10%"><b>Qty</b></td>
<td align="right" width="10%"><b>Total Price</b></td>
</tr></table>
';
echo '<p>Your cart is currently empty.</p>';
}
?>