Requête SQL avec GET_ via PDO

<li id="text-3" class="widget-container widget_text"><h3 class="widget-title">Recherches par départements</h3>     <div class="textwidget"><br />
  <map name="carte_departementale" id="carte_departementale">
        <area shape="poly" coords="126,38,125,50,145,53,145,48,147,40,137,42" href="/admin?critere=60&pays=France" alt="Oise" title="Oise" >
        <area shape="poly"  coords="164,28,149,28,150,23,146,16,141,11,135,11,132,3,137,2,142,10,148,10,151,17,157,18,158,22,164,22" href="/admin?critere=59&pays=France" alt="Nord" title="Nord" >
        <area shape="poly" coords="145,27,136,23,126,20,122,18,123,7,131,4,135,11,137,14,142,14,142,17,145,17" href="/admin?critere=62&pays=France" alt="Pas-de-Calais" title="Pas-de-Calais" >

//*..etc...*//
<?php $critere = $_GET['critere']; ?>
 </map>
  <img name="carte_departementale" id="carte_departementale" src="images/carte.png" usemap="#carte_departementale" alt="Carte cliquable" title="Carte cliquable" height="259" width="281">

<?php
    try { 
      $base = new PDO('mysql:host=localhost; dbname=iplanet', 'root'. '');
      }
      catch(exception $e)  {
      die ('Erreur '.$e->getMessage());
      }
      $base->exec("SET CHARACTER SET utf8");
      $retour = $base ->query('SELECT id_societe, nom_societe, adr, adr2, cp, ville, tel, fax, mail FROM societe WHERE cp LIKE "'.$critere%.'"');
      echo "<table border=1><caption>Gestion des societes </caption>";
      ?>
<thead>
             <tr>
                <th> ID </th>
                <th>Nom</th>  
                <th>Adr</th>
                <th>Adr2</th>
                <th>CP</th>
                <th>Ville</th>
                <th>Tel</th>
                <th>Fax</th>
                <th>Mail</th>
              <!--<th><a onclick="popupas();"><img src="images/icoajout.png"></a></th>
              <th><a onclick="popuprs();"><img src="images/icorechercher.png"></a></th>-->
            </tr>
            </thead>
      <?php
      while ($data = $retour ->fetch()) {
      echo "<tr><td>".$data['id_societe']."</td>";
      echo "<td>".$data['nom_societe']."</td>";
      echo "<td>".$data['adr']."</td>";
      echo "<td>".$data['adr2']."</td>";
      echo "<td>".$data['cp']."</td>";
      echo "<td>".$data['ville']."</td>";
      echo "<td>".$data['tel']."</td>";
      echo "<td>".$data['fax']."</td>";
      echo "<td>".$data['mail']."</td>";
      ?>
       <td><a onclick="popupms(<?php echo $data['id_societe']; ?>);"><img src="images/icomodifier.png"></a> </td>
       <td><a onclick="popupss(<?php echo $data['id_societe']; ?>);"><img src="images/icosupprimer.png"></a> </td></tr>
      <?php
      }
      echo "</table>";
      $base = null;
      ?>