<?php
    $servername = "localhost";
    $username = "root";
    $password = "";
    $database = "";

    try {
        $conn = new PDO("mysql:host=$servername;dbname=$database", $username, $password);
        // set the PDO error mode to exception
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        }
    catch(PDOException $e)
        {
        echo "Connection failed: " . $e->getMessage();
        }

    $rank = $conn->prepare("SELECT rank FROM users WHERE username = :username");
    $rank->execute(array(
        ':username' => $_SESSION['user']['username']
    ));

    while ($check = $rank->fetch(PDO::FETCH_ASSOC)){
        if ($check['rank'] == 1) {
            echo 'Je bent admin.';
        }
    }
?>