php - `While` Not showing echo -

i'm having trouble getting echo showing up. think there problem while table in mysql should work normally. code

    <?php   $sql = $db->prepare('select             topic_id,             topic_subject                     topics                     topics.topic_id = :topid'); $sql->bindparam(':topid', $_get['id'], pdo::param_int);  $sql->execute(); $result = $sql->rowcount();            if($result === false){             echo 'the topic not displayed, please try again later.';         }         elseif(count($result) === 0){             echo 'this topic doesn&prime;t exist.';         }     else         {         while($row = $sql->fetch())         {             //display post data             echo '<table class="topic" border="1">                     <tr>                         <th colspan="2">' . $row['topic_subject'] . '</th>                     </tr>'; ?> 

the while should show because topic exists in mysql. when i'm using avar_dump($sql->errorinfo()); say's array(3) { [0]=> string(5) "00000" [1]=> null [2]=> null } null because created topic in mysql test.

$result = $sql->rowcount();  elseif(count($result) === 0){ 

$result being assigned row count; count() designed count elements in array. manual

 if var not array or object implemented countable interface, 1 returned. there 1 exception, if var null, 0 returned.  

i think need is:

elseif($result === 0){ 

what think's happening there no results query, call count() isn't working. it's passing check, , since there no records retrieve, it's not going loop.