SELECT COUNT(*) returns 1 even if the request should return 0
<p>When I'm trying to get the number of rows on a SQL request and if not, the connection that follow fails. 
But in any case (also if the request should return 0), it returns 1.
Here's my code :</p>

<pre><code>$str = 'SELECT count(*) FROM admins WHERE mail = ? AND mdp = ?';
$arr = array($mail, $pass);
$rqt = sendRqt($str, $arr);
$tab = $rqt-&gt;fetchColumn();
$cnt = count($tab);
echo $cnt;
</code></pre>

<p>I don't understand why there's no time it returns 0</p>