Hello!
I have been working on a shopping cart and just have one last bit of code to shlog through, but I can't get it to work. I need to update the quantity (pd_qty) on tbl_product by deleting the quantity (od_qty) that was ordered, as taken from tbl_order_item. This should be done for each product (pd_id).

//update stock quantity
$i = 0;
$purchases[$i] = array();
$sql = "SELECT pd_id, od_qty
FROM tbl_order_item
WHERE od_id = $orderId";
$result = dbQuery($sql);
$row = dbFetchAssoc($result); //$row['pd_id'] and $row['od_qty']
$numRows = count($row);
for ($i = 0; $i < $numRows; $i++)
{
array_push($purchases[$i], $row['pd_id'], $row['od_qty']);
}

for ($i = 0; $i < $numRows; $i++)
{
$orderedQuantity = $purchases[$i]['od_qty'];
$productId = $purchases[$i]['pd_id'];
$sql = "UPDATE tbl_product
SET pd_qty = pd_qty - '$orderedQuantity'
WHERE pd_id = '$productId'";
$result = dbQuery($sql);
}
Any help would be immensely appreciated! Thank you :D