Question

I have a shopping cart form that once I submit the form I loop the POST values to print it on a table.Here is the loop for the items sold

<?php
    for($i = 0; $i < count($_POST["id"]); $i++){
        echo "<tr>";
        echo "<td>".$_POST["name"][$i]."</td>";
        echo "<td>$ ".$_POST["price"][$i]."</td>";      
        echo "<td>".$_POST["quantity"][$i]."</td>";
        $total[$i] = $_POST["price"][$i]*$_POST["quantity"][$i];
        echo "<td>$ ".$total[$i]."</td>";
        echo "</tr>"; 
 ?>

My question is based on this loop I need to compare it to a product DB that has the following fields

|Name | Price | QtyLeft | QtySold | where QtyLeft is the current quantity in stock. So based on the code above how do I query my table to subtract the quantity of the item sold to the QtyLeft and update QtySold?

Answer 1

For each item in the loop:

$quantity = intval($_POST["quantity"][$i]);
$id = intval($_POST["id"]);
$sql = "UPDATE product SET QtyLeft = QftLeft - $quantity, QtySold = QtySold + $quantity WHERE id = $id";