shopping cart: need to output ordered items - php

Question

The other page that is the index page shows the catalog of the pizzashop. Each pizza is a hyperlink that passes the id to this page.
The core of my question is in the code that starts with the foreach loop. I would like to simply read out of the database based on the SELECT query at hand.
I know it is weird to put the query IN the loop but for now it is the only way I figured out how to loop through all the ids that are in the SESSION array.
I tried many things to output the return that the query is supposed to give, I fiddled around with the mysqli_stmt thing, all giving me numerous types of errors.
<?php
session_start();
require 'pizza_sc_fns.php';
require 'header.php';
#$pizzaId = $_GET['pizza_id'];
if (!isset($_SESSION['order']))
{
$_SESSION['order'] = array();
$_SESSION['items'] = 0;
$_SESSION['totalprice'] = 0.00;
}
if (isset ($_SESSION['order'][$pizzaId]))
{
echo $_SESSION['order'][$pizzaId]++;
echo "\$_SESSION['order'][\$pizzaId] is SET \n";
}
else
{
echo $_SESSION['order'][$pizzaId] = 1;
}
$conn = connect2db();
foreach ($_SESSION['order'] as $pizzaItem)
{
$query = "SELECT pizza_name FROM pizzas WHERE pizza_id = $pizzaItem";
$res = #$conn->query($query);
echo $res->fetch_assoc();
echo "<hr />";
//$query = mysqli_prepare($conn, "SELECT * FROM pizzas WHERE pizza_id=$pizzaItem");
//echo var_dump($query)."<br />";
//$stmt_exec = mysqli_stmt_fetch($query);
//print $pizzaItem."<br />";
}
?>
Destroy session >>

Answer 1

You are going to need to use a loop but you don't need to run the query for every iteration. You can use the in clause.
Your code would be something like
$query = 'Select pizza_name from pizzas where id in (';
foreach($_SESSION['order'] as $pizza_id) {
$query.= mysql_real_escape_string($pizza_id).', ';
}
$query= substr($query, 0, -2); //Get rid of the trailing comma and space
$query .= ')';
And you can run the query.
I would recommend that you use prepared statements though I'm not sure how to use them for an in statement.