title: MySql and PDO: How to send a null param with bindParam()
body: <p>The value of the param $isConfirmed can be null, 0 or 1. When I try to send "null", PDO is returning me an Exception. How can I resolve that problem ?</p>
  
  <pre><code>$dbHandler = $dbConnection-&gt;prepare("INSERT INTO `Group` (visitId, guideId, groupSize, isConfirmed) VALUES (:visitId, :guideId, :groupSize, :isConfirmed)");
          for($i = 0; $i &lt; count($groupId); $i++) { 
                  $dbHandler-&gt;bindParam(":visitId", $visitId, PDO::PARAM_INT); 
                  $dbHandler-&gt;bindParam(":guideId", $guideId, PDO::PARAM_INT); 
                  $dbHandler-&gt;bindParam(":groupSize", $groupSize, PDO::PARAM_INT); 
                  $dbHandler-&gt;bindParam(":isConfirmed", $isConfirmed, PDO::PARAM_INT); 
                  $dbHandler-&gt;execute(); 
          }
  </code></pre>