json_decode使用mysqli返回1的数组

Question

I need to display all products from a table called cart. However, no matter how many products there are on the table, json_decode always return an array of 1 product on user side (check the var_dump). The user can only see last product added. json only shows last row of table. I need it to show all products. I have tried many things to debug this app but I think im not fully understanding json functionalities.

var_dump($items) : array(1) { [0]=> array(4) { ["id"]=> string(2) "14" ["size"]=> string(1) "0" ["quantity"]=> string(1) "1" ["available"]=> string(1) "1" } }

cart.php

<?php
if($cart_id !=''){
    $cartQ = $db->query("SELECT * FROM cart WHERE id ='{$cart_id}' ");
    $result = mysqli_fetch_assoc($cartQ);
    $items =  json_decode($result['items'],true);
    $i = 1;
    $sub_total = 0;
    $item_count = 0;
}
?>
     <?php
              foreach($items as $item){ 

               var_dump($items);
                  $product_id = $item['id'];
                  $productQuery = $db->query("SELECT * FROM product WHERE id ='{$product_id}' ");
                  $product = mysqli_fetch_assoc($productQuery);

              ?>

       <tr class="p">
    <td class="image"><img src="<?=$product['image_1'];?>" /></td>
    <td class="name"><?=$product['prod_name'];?></td>
    <td class="price"><?=money($product['price']);?></td>
    <td class="quantity"> <?=$item['quantity'];?></td>
    <td class="pricesubtotal"><?=money($item['quantity'] * $product['price'] );?></td>
    <td class=""><div><button name='removeitem' onclick="update_cart('removeitem','<?=$product_id['id'];?>');">&times</button></div></td>
  </tr>
  <?php endif;?>

Answer 1

You have lot's of problems with your data. First of all your should not be saving items as json. Or at the very least you should not be saving the item id inside the json object. Then you would be able to make use of the time honoured INNER JOIN to get all your products very easily, with minimal code and very fast.

SELECT * FROM products INNER JOIN cart on cart.item_id = product.id
WHERE cart.id = ?

As a side note, you should be using prepared statements instead of string concat for your query.