How To Used Order_id As Invoice Number And Converting Any Variable As Gloabal

I tried multiple times but have been stucked for long time, kindly mention that which method is better S_SESSION or GET Method to used some variable as global. And how to $date =

Solution 1:

To use $_SESSION, you have to run session_start(); before your php code starts:

<?php
  session_start(); 

  if(isset($_POST['order']))
  {
     $user_id  = $_SESSION['id'];
     $date     = date('Y-m-d H:i:s');
     $username = $_SESSION['username'];
     mysql_query("INSERT INTO tborder(user_id,`date`,username) VALUES('$user_id','$date','$username')") or die(mysql_error());
     $i = mysql_insert_id();
     if($i >0)
        for($l=0;$l<count($_POST['product_id']);$l++)
        {
            $product_id = $_POST['product_id'][$l];
            $quantity   = $_POST['quantity'][$l];
            $price      = $_POST['price'][$l];
            $discount   = $_POST['discount'][$l];
            $amount     = $_POST['amount'][$l];
            $username   = $_SESSION['username'];
            $user_id    = $_SESSION['id'];

            if(!isset($_SESSION['product_cart']))
                 $_SESSION['product_cart'] = [];

            if(!isset($_SESSION['product_cart']['products']))
                 $_SESSION['product_cart']['products'] = [];

            // save product to cart products array in $_SESSION
            $_SESSION['product_cart']['products'][] = [
                'id' => $product_id;
                'quantity'  => $quantity;
                'price'     => $price;
                'discount'  => $discount;
                'amount'     => $amount;
                'username'  => $username;
                'user_id'   => $user_id;
            ];

            // I don't get what is this query for
            mysql_query("INSERT INTO tborderdetail(order_id,product_id,quantity,price,discount,amount,username,user_id) VALUES('$i','$product_id','$quantity','$price','$discount','$amount','$username','$user_id')")or die(mysql_error());

         }

        // redirect after loop ends, 
        // unless it'll process only first array element 
        header('location:order.php');
     }

// Do not include html templates before you not sure you'll stay on this page
include('header.php');