登录后如何显示用户名或名字或名字php？

Question

I'm making a login system and I'm trying to make it once the user is logged in it will display the users username or first name. I figured out how to display the ID of the user but I want the username (uid is how I have it setup) or first name (first is how I have it set up).

<?php
if (isset($_SESSION['id'])) {
    echo $_SESSION['id'];
    echo "<div class='welcome_login'><h1>Welcome! Thanks for logging in!!</h1></div>";
} else {
    echo "<div class='intro_page'><h1>You must login or signup!</h1></div>";
}
?>

Answer 1

You have to do a database lookup for the user that have the id stored in the session $_SESSION['id'] or you can store the user firstname and lastname as an array in the session :

$user = [ 'firstname' => "user firstname queried from database",
          'lastname' => "user lastname queried from database"
        ]
$_SESSION['user'] = $user; 

then you can do

echo "<div class='welcome_login'><h1>Welcome!",$_SESION['user']['firstname'] ," Thanks for logging in!!</h1></div>";

i recommend you see this tutorial : https://www.youtube.com/playlist?list=PLE134D877783367C7

for a great login and registration system