从数据库中的表中获取一个特定字段并在会话中使用它

I'm currently building a website that has a log in form. Depending on which role this user has a navigation bar has to be displayed accordingly.

For Example : Someone who hasn't yet logged in will have a "login" link. If someone has logged in and is not an admin a different nav bar is displayed.

All log in details are stored in a db and this has to be done using sessions since it will send the user to a different page.

Any ideas ?

Code till now :

$query = "SELECT count(*) FROM tbl_users
            WHERE username = '$username' AND password = '$pass'";

$result = mysqli_query($connection, $query)
        or die("Error in query: ". mysqli_error($connection));

$row = mysqli_fetch_row($result);
$counter = $row[0];

if($counter > 0)
{
    session_start();
    $_SESSION['user']= $username;
    $_SESSION['role'] = $row['role'];

a somewhat vague question but, check your role.

if($_SESSION['role']=='admin')
    echo 'I am admin';
elseif($_SESSION['role']=='customer')
    echo 'I am customer';
else
    echo 'No valid role / not logged in';