Requete pour un UPDATE

<form method="post" action="">
<select name="classe">
<option value="PS">PS</option>
<option value="MS">MS</option>
<option value="GS">GS</option>
<option value="CP">CP</option>
<option value="CE1">CE1</option>
<option value="CE2">CE2</option>
<option value="CM1">CM1</option>
<option value="CM2">CM2</option>
</select>
<input type="submit" value="Tri par classe" name="sub_classe" /><?php echo '<a href="logout.php">Déconnexion</a>';?>
</form>
<?php
$db = mysql_connect('xxxxx', 'xxxxxx', 'xxxxx') or die('HOST ?');
mysql_select_db('xxxxxx',$db);
if(isset($_POST['sub_classe']) && $_SERVER['REQUEST_METHOD']==='POST'){
$classe = $_POST['classe'];
$sql = "SELECT * FROM sortie1 where Classe='".$classe."' "; /*pareil*/ 
$req=mysql_query($sql) or die ('Erreur SQL !<br>'.$sql.'<br>'.mysql_error());?>
<?php
echo '<table align="center" border="1">'; 
echo '<tr>

<td>id</td>
<td>Nom</td>
<td>Prenom</td>
<td>Classe</td>
<td>Telephone</td>
<td>Portable_M</td>
<td>Portable_P</td>
<td>Sortie</td>
<td>Participation</td>
</tr>'; 

while($data = mysql_fetch_assoc($req)){ 
 echo '<tr>

<td><value='.$data['id'].'>'.$data['id'].'</td>
<td><value='.$data['Nom'].'>'.$data['Nom'].'</td>
<td><value='.$data['Prenom'].'>'.$data['Prenom'].'</td>
<td><value='.$data['Classe'].'>'.$data['Classe']. '</td>
<td><value='.$data['Telephone'].'>'.$data['Telephone'].'</td>
<td><value='.$data['Portable_M'].'>'.$data['Portable_M'].'</td>
<td><value='.$data['Portable_P'].'>'.$data['Portable_P'].'</td>
<td><value='.$data['Sortie'].'>'.$data['Sortie'].'</td>
<td><input type="text" name="Participation" size="10" value="" maxlength="10"></td>
</tr>'; 

} 
echo '</table>'; 
echo '</div><hr>'; 
?>
<?php
}else{
$sql = 'SELECT * FROM sortie1'; 
$req=mysql_query($sql) or die ('Erreur SQL !<br>'.$sql.'<br>'.mysql_error());
echo '<div align="center">'; 
echo '<table border="1">'; 
echo '<tr>

<td>Nom</td>
<td>Prenom</td>
<td>Classe</td>
<td>Telephone</td>
<td>Portable_M</td>
<td>Portable_P</td>
<td>Sortie</td>
<td>Participation</td>
</tr>'; 

while($data = mysql_fetch_assoc($req)){ 
echo '<tr>

<td>'.$data['Nom'].'</td>
<td>'.$data['Prenom'].'</td>
<td>'.$data['Classe'].'</td>
<td>'.$data['Telephone'].'</td>
<td>'.$data['Portable_M'].'</td>
<td>'.$data['Portable_P'].'</td>
<td>'.$data['Sortie'].'</td>
<td>'.$data['Participation'].'</td>
</tr>'; 

} 
echo '</table>'; 
echo '</div><hr>'; 
}
?>
    <p align="center">
      <input type="submit" value="Envoyer" name="envoyer">
    </p>'

<form method="post" action="">
<select name="classe">
<option value="PS">PS</option>
<option value="MS">MS</option>
<option value="GS">GS</option>
<option value="CP">CP</option>
<option value="CE1">CE1</option>
<option value="CE2">CE2</option>
<option value="CM1">CM1</option>
<option value="CM2">CM2</option>
</select>
<input type="submit" value="Tri par classe" name="sub_classe" /><?php echo '<a href="logout.php">Déconnexion</a>';?>
</form>
<?php

if(isset($_POST['participe']) && isset($_POST['idtoupdate'])){
$db = mysql_connect('?', '?', '?') or die('HOST ?');
mysql_select_db('?',$db);
$id=mysql_real_escape_string($_POST['idtoupdate']);
$id=(int)$id;/*cast force le type à integer, on a un entier*/
$participation=mysql_real_escape_string($_POST['Participation']);
//UPDATE Persons SET Age = '36' WHERE FirstName = 'Peter' AND LastName = 'Griffin'");
//http://www.w3schools.com/php/php_mysql_update.asp
$sql = "update latable set participation='".$participation."' where id='".$id."' limit 1"; /*là je connais pas les champs*/
  
  if(mysql_query($sql)){
  //ok
  }else{
  echo 'Update raté';
  }

mysql_close();
}else{
//rien d envoyer
}

$db = mysql_connect('localhost', 'root', '') or die('HOST ?');
mysql_select_db('a',$db);
if(isset($_POST['sub_classe']) && $_SERVER['REQUEST_METHOD']==='POST'){
$classe = $_POST['classe'];
$sql = "SELECT * FROM sortie1 where Classe='".$classe."' "; /*pareil*/ 
$req=mysql_query($sql) or die ('Erreur SQL !<br>'.$sql.'<br>'.mysql_error());?>
<?php
echo '<table align="center" border="1">'; 
echo '<tr>

<td>id</td>
<td>Nom</td>
<td>Prenom</td>
<td>Classe</td>
<td>Telephone</td>
<td>Portable_M</td>
<td>Portable_P</td>
<td>Sortie</td>
<td>Participation</td>
</tr>'; 

while($data = mysql_fetch_assoc($req)){ 
 echo '<tr>

<td><value='.$data['id'].'>'.$data['id'].'</td>
<td><value='.$data['Nom'].'>'.$data['Nom'].'</td>
<td><value='.$data['Prenom'].'>'.$data['Prenom'].'</td>
<td><value='.$data['Classe'].'>'.$data['Classe']. '</td>
<td><value='.$data['Telephone'].'>'.$data['Telephone'].'</td>
<td><value='.$data['Portable_M'].'>'.$data['Portable_M'].'</td>
<td><value='.$data['Portable_P'].'>'.$data['Portable_P'].'</td>
<td><value='.$data['Sortie'].'>'.$data['Sortie'].'</td>
<td>
<form method="post" action="">
<input type="hidden" name="idtoupdate" value="'.$data['id'].'">
<input type="text" name="Participation" size="10" value="" maxlength="10">
<input type="submit" name="participe" value="Mettre à jour">
</form>
</td>
</tr>'; 

} 
echo '</table>'; 
echo '</div><hr>'; 
?>