php mysql shopping cart updating quantity error - php

Question

I am new to coding and trying to update quantities in my cart, but it only accepts for one product.
If I add more than one, I can only update the last product, which will also set all the other products to the same quantity.
I need help separating the quantities.
Here is my code:
<form action="" method="post" enctype="multipart/form-data">
<table align="center" width="700" >
<tr align="center">
<td colspan="5"><h2>SHOPPING CART</h2></td>
</tr>
<tr align="center">
<th>Remove</th>
<th>Product (s)</th>
<th>Quantity</th>
<th> Price</th>
<th> Total Price</th>
</tr>
<?php
global $con;
$total = 0;
$ip = getIp();
$sel_price = "select * from cart where ip_add='$ip'";
$run_price = mysqli_query($con,$sel_price);
while($p_price = mysqli_fetch_array($run_price)){
$pro_id = $p_price['p_id'];
$pro_price = "select * from products where product_id = '$pro_id'";
$run_pro_price = mysqli_query($con, $pro_price);
while($pp_price = mysqli_fetch_array($run_pro_price)){
$product_price = array($pp_price['product_price']);
$product_id = $pp_price['product_id'];
$product_title = $pp_price['product_title'];
$product_image = $pp_price['product_image'];
$single_price = $pp_price['product_price'];
$values = array_sum($product_price);
$total += $values;
?>
<tr align = "center">
<td><input type="checkbox" name="remove[]" value=" <?php global $con; echo $pro_id; ?>"/></td>
<td><span style="color: white;"><?php echo $product_title; ?></span>
<br>
<img src="admin_area/product_images/<?php echo $product_image; ?>" width="100px" height="100px"></td>
<td><input type="number" size="4" name="qty" /></td>
<?php
global $con;
global $Stotal;
$Stotal = $single_price;
if(isset($_POST['update_quantity'])){
$qty = $_POST['qty'];
$update_qty = "update cart set qty='$qty' ";
$run_qty = mysqli_query($con, $update_qty);
$Stotal = $single_price * $qty;
}
?>
<td><?php echo "KSh. " . $single_price; ?></td>
<td><?php echo "KSh. " . $Stotal; ?></td>
</tr>
<?php }} ?>
<tr align="right">
<td colspan="5"><b>Total:</b> <?php echo "KSh. " . $total; ?></td>
</tr>
<tr align="center">
<td><input type="submit" name="update_cart" value="Update Cart" /></td>
<td><input type="submit" name="continue" value="Continue Shopping" /></td>
<td><input type="submit" name="update_quantity" value="Update Quantity" /></td>
<td><button> Checkout </button></td>
</tr>
</table>
</form>
<?php
global $con;
$ip = getIp();
if(isset($_POST['update_cart'])){
foreach($_POST['remove'] as $remove_id){
$delete_pro = "delete from cart where p_id = '$remove_id' and ip_add='$ip'";
$run_delete = mysqli_query($con, $delete_pro);
if($run_delete){
echo "<script>window.open('cart.php','_self')</script>";
}
}
}
if(isset($_POST['continue'])){
echo "<script>window.open('index.php','_self')</script>";
}
?>

Answer 1

Looks like you are naming HTML form controls as 'PHP arrays'. <input name="remove[]">
These form element names can only be alphanumeric, and on the server you can differentiate the elements by for instance postfixing the id of the product to the form control name and checking it there.
By the way, I recommend using $_SESSION for cart handling