How can the MySQL Update function be used to track user online/offline status in a PHP application?
To track user online/offline status in a PHP application using MySQL Update function, you can have a column in your users table to store their online status. When a user logs in, update the status to 'online', and when they log out, update it to 'offline'. This way, you can easily track the user's online status in real-time.
// Update user online status to 'online' when they log in
$user_id = $_SESSION['user_id'];
$sql = "UPDATE users SET status = 'online' WHERE id = $user_id";
$result = mysqli_query($conn, $sql);
// Update user online status to 'offline' when they log out
$user_id = $_SESSION['user_id'];
$sql = "UPDATE users SET status = 'offline' WHERE id = $user_id";
$result = mysqli_query($conn, $sql);