include user ID in session - php

Question

Currently my php login form will only carry acrocss the username on the session, I want this to carry across the user id (automatically created when the user registers).
As shown below I have included the user_id but it is not displaying on my webpage, the username is however.
Just wondering if anyone can help me with this? (I'm new to PHP)
Login process:
require_once('connection.php');
session_start();
if(isset($_POST['login']))
{
if(empty($_POST['username']) || empty($_POST['PWORD']))
{
header("location:login.php?Empty= Please Fill in the Blanks");
}
else
{
$query="select * from users where username='".$_POST['username']."' and PWORD='".$_POST['PWORD']."'";
$result=mysqli_query($con,$query);
if(mysqli_fetch_assoc($result))
{
$_SESSION['User']=$_POST['username'];
$_SESSION['user_id'] = $row['user_id'];
header("location:../manage_event.php");
}
else
{
header("location:login.php?Invalid= Please Enter Correct User Name and Password ");
}
}
}
else
{
echo 'Not Working Now Guys';
}
Session on next page:
session_start();
if(isset($_SESSION['User']) || isset($_SESSION['user_id']))
{
echo ' Welcome ' . $_SESSION['User'].'<br/>';
echo ' User ID ' . $_SESSION['user_id'].'<br/>';
}
else
{
header("location:login/login.php");
}

Answer 1

Though your security is questionable, i’ll answer your question anyway. As stated in another response you aren’t assigning your variables the right way. See an example here
The following code will fix your problems contrary to the other solution:
$query="select * from users where username='".$_POST['username']."' and PWORD='".$_POST['PWORD']."'";
if ($result = mysqli_query($con, $query)) {
/* fetch associative array */
while ($row = mysqli_fetch_assoc($result)) {
$_SESSION['User']=$_POST['username'];
$_SESSION['user_id']=$row['user_id'];
header("location:../manage_event.php");
}
}else {
header("location:login.php?Invalid= Please Enter Correct User Name and Password ");
}
}
Make sure to replace this code with your old fetching code block. Thus in the first ‘else’ clause.

Answer 2

How about assigning the fetched result to $row:
$query="select * from users where username='".$_POST['username']."' and PWORD='".$_POST['PWORD']."'";
$result=mysqli_query($con,$query);
if( $row = mysqli_fetch_assoc($result))
{
$_SESSION['User']=$_POST['username'];
$_SESSION['user_id'] = $row['user_id'];