predpripravovane prikazy

zdar
u priblizne u neceho takovehoto(prepared statements):
protected function dva(){
$spojist=new mysqli("db", "nick", "heslo", "db");
$spje=$spojist->prepare("SELECT mail FROM uzivatel WHERE nick=?" );
$spje->bind_param("s", $_SESSION['znick']);
$spje->execute();
$spje->bind_result($rada);
$spje->fetch();
print($rada);
$spje->close();
$spojist->close();
}
mi to vypise misto:taurendilcz@gmail.com neco takovehoto tozneX3Q �3Q.(Zkouseno i s while)
musi byt chyba v prikazu protoze u tohoto co jsem napsal to fara:
protected function dva(){
$spojist=new mysqli("db", "nick", "heslo", "db");
$spje=$spojist->query("SELECT mail FROM uzivatel WHERE nick='" . $_SESSION['znick'] . "'" );
while($radek=$spje->fetch_row()){
echo $radek[0];
}
}
Kde delam tu chybu?:( dik