在每个PHP中添加总和

Question

$connect = mysqli_connect("localhost", "root", "", "hempbag_db") or die("Connection failed");

foreach($a as $b){ 
    foreach($b as $c){
        $query5 = "SELECT P_price tbl_products WHERE PID='".$c['PID']."' ";
        $get_price = mysqli_query($connect, $query5);
        $get_price1 = mysqli_fetch_assoc($get_price); 
        $price = ($get_price1['P_price'])+ $price + 0; // This does not add
    }
}

$price does not add only takes the last value of the data inside the loop.

How can I add them?

I also used:

$price = ($get_price1['P_price'])+0;
$new_price += $price;

Still failed.
Thank You!

Answer 1

Try this: $total_price is sum of price.

$connect = mysqli_connect("localhost", "root", "", "hempbag_db") or die("Connection failed");

$total_price = 0;
foreach($b as $c) {
    $query5 = "select P_price from tbl_products where PID='".$c['PID']."' ";
    $get_price = mysqli_query($connect, $query5);
    $get_price1 = mysqli_fetch_assoc($get_price);
    $total_price += $get_price1['P_price'];
}

echo $total_price;

Answer 2

initialise $price before looping through the array.

$connect = mysqli_connect("localhost", "root", "", "hempbag_db") or die("Connection failed");

$price = 0;
foreach($b as $c)
{
  $query5 = "select P_price from tbl_products where PID='".$c['PID']."' ";
  $get_price = mysqli_query($connect, $query5);
  $get_price1 = mysqli_fetch_assoc($get_price); 
  $price = ($get_price1['P_price'])+$price;
  // other way (highly recommended)
  $price += ($get_price1['P_price']);
}