Simple PHP Shopping Cart

addtocart.php

<?php   
//Add to cart
   if($action=='addcart' && $_SERVER['REQUEST_METHOD']=='POST') {	
        //Finding the product by code
        $query = "SELECT * FROM products WHERE sku=:sku";
        $stmt = $conn->prepare($query);
        $stmt->bindParam('sku', $_POST['sku']);
        $stmt->execute();
        $product = $stmt->fetch();
        
        $currentQty = $_SESSION['products'][$_POST['sku']]['qty']+1; //Incrementing the product qty in cart
        $_SESSION['products'][$_POST['sku']] =array('qty'=>$currentQty,'name'=>$product['name'],'image'=>$product['image'],'price'=>$product['price']);
        $product='';
        header("Location:shopping-cart.php");
    }