我有两页产品和购物车，但问题是当我发布$_SESSION['itemcode']到购物车页面select query working时，当页面重定向到产品作为continue shopping旧产品的新产品覆盖时？
产品页面
session_start();
if(isset($_POST['size']))
{
$_SESSION['pid']= implode (",",$_POST['pid']);
$_SESSION['wid2']=$_POST['wid'];
$_SESSION['itemcode3']=$_POST['itemcode'];
if($_REQUEST['command']=='add' && $_REQUEST['id']){
$id=$_REQUEST['id'];
addtocart($id,1);
header('location:shoppingcart.php');
exit();
}
<input type="button" class="button1" name="check" value="Add To Cart"
onclick="addtocart(<?php echo $row3['id'];?>);" />
$length= count($_POST['product']);
for($i=0; $i<$length; $i++)
{
$size=$_POST['size'];
$query2=mysql_query("INSERT INTO mywishlist VALUES
('','$id','".$_SESSION['id']."','".$_SESSION['email']."','".$_POST['itemcode']
[$i]."','".$_POST['product'][$i]."','$size','".$_POST['price']
[$i]."','".$_POST['image1'][$i]."','')")
or die ("My Wish List");
}
购物车页面
session_start();
$itemcode2=implode(',',$_SESSION['itemcode3']);
$querycart=mysql_query("SELECT * FROM products INNER JOIN mywishlist ON
products.`id`=mywishlist.`pid`
WHERE mywishlist.itemcode='".$itemcode2."' ")
or die ("shoppingcart query");
while($rowcart=mysql_fetch_assoc($querycart))
{
?>
<?php echo $rowcart['itemcode']; ?>
<?php echo $rowcart['products']; ?>
<?php echo $rowcart['qty']; ?>
<?php echo $rowcart['price']; ?>
<?php }?>