Using Session code instead of PHP SELECT WHERE function - php

Question

Since my question may be unclear:
in short I am wanting to make the following code shorter and/or faster
I have login system that starts a session and runs until you logout
I also have a SELECT WHERE script that counts how many invoices have not been paid that is working just fine but is long, ugly, and bulky like so:
<?php
$con=mysqli_connect("REMOVED FOR SECURITY");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT COUNT(*) FROM mypanda_invoices
WHERE is_paid='0'");
while($row = mysqli_fetch_array($result))
{
echo "<span class='badge badge-important'>" . $row['COUNT(*)'] . "</span>";
}
?>
Right now to get the users username I have: <?php session_start(); echo $_SESSION['username']; ?> is there someway I could do this same type of thing with the code I have above? Just to make it shorter and take advantage of the session??? Thank you in advance.

Answer 1

As long as the session has started, you can put the invoice count in the session as well.
If you want the code cleaner, I would recommend checking for a result set and then using fetch_object()->inv_count (or, in PHP 5.4, you could use fetch_array(MYSQLI_NUM)[0] I guess).
If you have an error with a vital part of your system -- the database connection for example, you should handle it gracefully (my die below isn't graceful, but it gets the job done) instead of just echoing and continuing on, which will result in a fatal error later on.
Also, using objects will make things a bit cleaner as well.
<?php
$con = new mysqli("REMOVED FOR SECURITY");
// Check connection
if(mysqli_connect_errno()) die("Failed to connect to MySQL: " . mysqli_connect_error());
$result = $con->query("SELECT COUNT(*) AS inv_count FROM mypanda_invoices
WHERE is_paid='0'");
if($result && $result->num_rows) $_SESSION['inv_count'] = $con->fetch_object()->inv_count;
else $_SESSION['inv_count'] = 0;
echo "<span class='badge badge-important'>" . $_SESSION['inv_count'] . "</span>";