Making user pages using PHP and MYSQL by getting user_name from URL: user/username

This is a pretty broad topic, what you need to do is parse the url - IE break it into parts and then match the url to a set of actions. This is commonly known as routing.

A naive implementation would be a:

$parts = explode($_SERVER['REQUEST_URI'], '/'); if ( $parts[-2] === 'user' && $parts[-1] ) { $stmt = $pdo->prepare("SELECT * FROM 'users' WHERE username = ? OR id = ?"); $result = $stmt->execute(array($parts[-1], array($parts[-1])); // ... do something if the user is found or not. } 

But this would fail if the url contains query parameters (?foo=bar) or a hash (#foo).

Instead you can use parse_url to make sure you only use the path.

$path = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH); $parts = null; // Match the url with a regular expression. preg_match(/^\/user\/(\w*)$/, $path, $parts); if ( count($parts) == 2 ) { $stmt = $pdo->prepare("SELECT * FROM 'users' WHERE username = ? OR id = ?"); $result = $stmt->execute(array($parts[-1], array($parts[-1])); // ... do something if the user is found or not. } 

But in the end you might want consider using a micro framework such as Silex, Slim or using the Routing component from Symfony2 so that you can concentrate on building your application rather than reinventing the wheel.

It might be better if you use Url Rewriting (aka friendly urls)

You can see this link which answers this same question, although your case is a little bit different. Apache friendly urls

Since you can't convert $id to $username (both are different values) I would recommend to change the link to 'user/ID' instead of 'user/USERNAME'.