How can one compare if a user is present in the user database while reading posts in a forum?

To compare if a user is present in the user database while reading posts in a forum, you can query the database to check if the user exists based on their username or user ID. If the user is found in the database, you can display personalized information or options for that user. 

// Assuming $db is the database connection
$user_id = $_SESSION['user_id']; // Get the user ID from the session

// Query the database to check if the user exists
$query = "SELECT * FROM users WHERE id = $user_id";
$result = mysqli_query($db, $query);

if(mysqli_num_rows($result) > 0) {
    // User exists in the database
    $user = mysqli_fetch_assoc($result);
    echo "Welcome back, " . $user['username'] . "!";
} else {
    // User does not exist in the database
    echo "User not found in the database.";
}

Keywords

PHP user database forum authentication comparison

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