PHP add up all values from foreach() - php

Question

I am making a shopping cart system, and my session is being displayed with a foreach() function. Inside this function, i have a variable called $item_price. I would like all the $item_price's to be added up so that I end up with the grand total.
How could this be done? I have no clue to how this problem should be solved :/
This is my foreach() code:
foreach($session_cart as $cart_items) {
$fetch_info = mysql_query("SELECT * FROM `shop_items` WHERE item_id = '$cart_items'");
while($shop_items = mysql_fetch_array($fetch_info)) {
$item_id = $shop_items['item_id'];
$item_name = $shop_items['item_name'];
$item_quantity = count(array_keys($session_quantity, $item_id));
$item_price = $shop_items['item_price'] * $item_quantity; }
$cartOutput .= '<h2>'.$item_name.'</h2>';
$cartOutput .= '<a> Quantity: '.$item_quantity.'</a><br>';
$cartOutput .= '<a> Price: '.number_format((float)$item_price, 2, '.', '').' USD</a><br>';
$cartOutput .= '<a> ID: '.$item_id.'</a><br><br>';
}

Answer 1

Use updated code:
$total = 0;
foreach($session_cart as $cart_items) {
$fetch_info = mysql_query("SELECT * FROM `shop_items` WHERE item_id = '$cart_items'");
// while($shop_items = mysql_fetch_array($fetch_info)) { //<- No need of loop here as only one will be returned everytime
$shop_items = mysql_fetch_assoc($fetch_info); //<- use this instead
$item_id = $shop_items['item_id'];
$item_name = $shop_items['item_name'];
$item_quantity = count(array_keys($session_quantity, $item_id));
$item_price = $shop_items['item_price'] * $item_quantity;
//} //<- Closing while loop removed
$cartOutput .= '<h2>'.$item_name.'</h2>';
$cartOutput .= '<a> Quantity: '.$item_quantity.'</a><br>';
$cartOutput .= '<a> Price: '.number_format((float)$item_price, 2, '.', '').' USD</a><br>';
$cartOutput .= '<a> ID: '.$item_id.'</a><br><br>';
$total+=$item_price; //<- Sums up for grand total
}
echo $total; //<- shows grand total

Answer 2

$total = 0;
foreach($array as $row)
{
$total += $row['item_price'];
//the rest of your code in foreach
}
echo $total;