$toto="select is_eval, MAX(eval_date) FROM cr_evaluation GROUP BY is_eval";
$req12 = mysql_query($toto) or die('Erreur SQL !<br>'.$toto.'<br>'.mysql_error()); 

while($data=mysql_fetch_assoc($req12)){
$eval_date            =$data['eval_date'];
$is_eval              =$data['is_eval'];

echo "<br>name: ".$is_eval." date: ".$eval_date;

}