Update one value in table sql - php

Question

I've tried a lot thing and a lot ideas, but i can't make this code run well.
I'm starting to build page for a shopping cart.
In these images i want update quantity each product separately in database using sql
When I update quantity product from website, I'd like to update just the product by p_id . not all products.
Lets say I have for example two product in my cart shop:
in this images i show u my database
And this is my work so far:
<form action="" method="post">
<table border="0" cellspacing="0" width="100%">
<tr colspan="5" class="title_incart">
<th colspan="2">product</th>
<th>qty</th>
<th>price</th>
<th>x</th>
</tr>
<?php
global $connect;
$ip = getIp();
$total = 0;
$t_price = "SELECT * FROM cart WHERE ip_add = '$ip'";
$run_price = mysqli_query($connect, $t_price);
while($row_t_price = mysqli_fetch_array($run_price)){
$pro_id_t = $row_t_price['p_id'];
$price_pro = "SELECT * FROM products WHERE p_id = '$pro_id_t'";
$run_price_pro = mysqli_query($connect, $price_pro);
while($row_price_pro = mysqli_fetch_array($run_price_pro)){
$pro_price = array($row_price_pro['p_price']);
$pro_title = $row_price_pro['p_title'];
$pro_img = $row_price_pro['p_img'];
$pro_price_single = $row_price_pro['p_price'];
$values = array_sum($pro_price);
$total +=$values;
?>
<tr colspan="5" class="info_incart">
<th><img class="res_img_incart" src="files/images/images_product/<?php echo $pro_img; ?>"/></th>
<th><?php echo $pro_title; ?></th>
<th><input type="text" name="abcd" size="1" value="<?php echo $_COOKIE['abcd']; ?>"/></th>
<?php
if(isset($_POST['update_cart'])){
$abcd = $_POST['abcd'];
$update_qty = "UPDATE cart SET abcd = '$abcd' WHERE p_id = '$pro_id_t'";
$run_u_qty = mysqli_query($connect, $update_qty);
$_COOKIE['abcd'] = $abcd;
$total = $total*$abcd;
}
?>
<th><?php echo $pro_price_single; ?> $</th>
<th><input type="checkbox" name="remove[]" value="<?php echo $pro_id_t; ?>"/></th>
</tr>
<?php } } ?>
<tr colspan="5" class="total_price_incart">
<th>Total price</th>
<th><?php echo $total; ?> $</th>
</tr>
<tr class="checkout_incart">
<th colspan="2">
<input type="submit" name="update_cart" value="update cart"/>
</th>
</tr>
</table>
</form>
i just want help on this part
<th><input type="text" name="abcd" size="1" value="<?php echo $_COOKIE['abcd']; ?>"/></th>
<?php
if(isset($_POST['update_cart'])){
$abcd = $_POST['abcd'];
$update_qty = "UPDATE cart SET abcd = '$abcd' WHERE p_id = '$pro_id_t'";
$run_u_qty = mysqli_query($connect, $update_qty);
$_COOKIE['abcd'] = $abcd;
$total = $total*$abcd;
}
?>
<input type="submit" name="update_cart" value="update cart"/>
Help me please, I want this for my school assignment, and I'm sorry about my English, in case there's anything wrong.
my friend i found the solution, after a lot trying
i used
$query = "UPDATE cart SET abcd= 'abcd + 1' WHERE p_id = '$pro_id'";
and its work fine, when i add product to my cart its add +1 on old value

Answer 1

You loop through your items, and check if $_POST['update_cart'] is set to update an item's quantity. But if $_POST['update_cart'] is set for one itteration, it will be set for all itterations. So you will update the quantity of each item in the loop.
What you could do, is give each input field a unique name. Not just name them all abcd. This way, you will be able to identiy the quantity for each item.
Something like this:
<tr colspan="5" class="info_incart">
<th><img class="res_img_incart" src="files/images/images_product/<?php echo $pro_img; ?>"/></th>
<th><?php echo $pro_title; ?></th>
<th><input type="text" name="abcd<?php echo $pro_id_t ?>" size="1" value="<?php echo $_COOKIE['abcd' + $pro_id_t]; ?>"/></th>
<?php
if(isset($_POST['update_cart'])){
$abcd = $_POST['abcd' + $pro_id_t];
$update_qty = "UPDATE cart SET abcd = '$abcd' WHERE p_id = '$pro_id_t'";
$run_u_qty = mysqli_query($connect, $update_qty);
$_COOKIE['abcd' + $pro_id_t] = $abcd;
$total = $total*$abcd;
}
?>
<th><?php echo $pro_price_single; ?> $</th>
<th><input type="checkbox" name="remove[]" value="<?php echo $pro_id_t; ?>"/></th>
</tr>