Shopping cart: Total cost.?

[SeenGee]

i'm using the following script as part of a mutli user shopping cart application made with php and postgres.
the problem i've been having is in calculating a total cost for all the items in the cart.
i would really appreciate any help people can offer me to make this work. thanks a lot.

In case its not obvious each time a row is added to the basket the sum cost is worked out for that row using:

$sumCost = $quantity*$price;

what i want is to be able to calculate is the total sum of every sum cost from every row in the basket, regardless of how many rows there are.

<?php
session_start();
?>
<?php
$DBconnection = pg_connect("");

if (!$DBconnection)
    {
        print"<h3>Error connecting to the database!</h3>";
    }
    else
    {
        $productid = $HTTP_POST_VARS["productid"];
        $quantity = $HTTP_POST_VARS["quantity"];
	//$tempsession = session_id();

//search basket1 for previous additions
$searchbasket = "select productid from basket where productid like '%$productid' AND tempsession like '%$PHPSESSID'";
    $dosearchbasket = pg_exec($DBconnection, $searchbasket);


//count number of rows returned from search result
$rowCounting = pg_numrows($dosearchbasket);

//if previous items exist, then update
if ($rowCounting>=1)
{
	//**UPDATING
	$Updatebasket = "update basket set quantity=$quantity where productid=$productid AND tempsession='$PHPSESSID'";
    	$doUpdateBasket = pg_exec($DBconnection, $Updatebasket);

    	if (!$doUpdateBasket)
    	{
    		print "<h2>Error adding  it to the basket</h2>";
    	}
}

//if previous items do not exist, then insert
if ($rowCounting==0)
{
	//**INSERTING
    	$addtobasket = "insert into basket values ($productid, $quantity, '$PHPSESSID')";
    	$doAddToBasket = pg_exec($DBconnection, $addtobasket);

    	if (!$doAddToBasket)
    	{
     		print "<h2>Error adding to the basket</h2>";
    	};
}


    $selectBasketContents = "select basket.productid, basket.quantity, products.name, products.brand, products.price from basket, products where basket.productid=products.id and basket.tempsession='$PHPSESSID'";
    $getBasketContents = pg_exec($DBconnection, $selectBasketContents);

    if(!$getBasketContents)
    {
        print "<h2>Failed selecting basket contents</h2>";
    }
    else
    {
        $rowCount = pg_numrows($getBasketContents);

        print "<center><table width=75% bgcolor=#C0D9D9 border=1>\n <th class=\"title\" colspan=\"8\">Basket Contents</th>";
        print"<tr width=75% bgcolor=#A8A8A8><td class=\"title\">Product ID</td><td class=\"title\">Name</td><td class=\"title\"> Brand</td><td class=\"title\">Price</td><td class=\"title\">Quantity</td><td class=\"title\">Total Price</td><td class=\"title\">Update</td><td class=\"title\">Delete</td></tr>\n";
        for($i; $i<$rowCount; $i++)
        {
            list($productid, $quantity, $name, $brand, $price) = pg_fetch_row($getBasketContents, $i);
            $sumCost = $quantity*$price;
            print "<tr><FORM ACTION=\"updatebasket.php\" METHOD=\"POST\"><td>$productid</td><input type=\"hidden\" name=\"productid\" value=\"$productid\"><td>$name</td><td>$brand</td><td>£$price</td><td><input type =\"TEXT\" name=\"quantity\" Size=\"4\" MAXLENGTH=\"5\" value=\"$quantity\"></td><td>£$sumCost</td><td><INPUT TYPE=\"submit\" VALUE=\"Update\"></td></FORM>";
	print "<td><FORM ACTION=\"alterbasket.php\" METHOD=\"POST\"><input type=\"hidden\" name=\"productid\" value=\"$productid\"><input type=\"hidden\" name=\"quantity\" value=\"$quantity\"><INPUT TYPE=\"submit\" VALUE=\"Delete\"></td></FORM></tr>";



        print"</table></center>";
    }
}
    pg_close();
?>

Thanks again

[The_Chancer]

Try $sumcost += $quantity*$price;

I.E. sumcost=sumcost+(quantity*price)

HTH