Ima li neko ideju kako ovo mogu popraviti?
include("../db.php");
session_start();
if ((!isset($_SESSION['a']) || empty($_SESSION['a']))) {
$sql = "SELECT role FROM users WHERE username='" . $_SESSION['a'] . "'";
$res = mysqli_query($con, $sql);
$row = mysqli_fetch_object($res);
$role = $row['role'];
if ($role != "admin") {
header("location: login.php");
}
}