Filter input, sanitize output

filtInput

<?php 
// if the value passed into the GET should be an int.
$intStorage = intval($_GET['someValue']);
// Using PDO
$db = new PDO();
$query = $db->prepare("SELECT someRow FROM table WHERE value = ?");
$query->bindParam(1,$bindedValue);
// The first argument is number of prepared statements, second is the value.
$query->execute();
// Boolean false if nothing is found.

?>