<?php
    $usuario = $_SESSION['username'];
    $pass = $_SESSION['password'];

    $results = $mysqli->query("SELECT Nombre, SUBSTRING(Nombre, 1,20) AS palabra,
                              IdUsuario, Username, Password
                              FROM Usuarios
                              WHERE Username='$usuario' AND Password ='$pass'");
    mysqli_set_charset("utf8");
    if($res = $results->fetch_array()) {}

    ?>