无法使用PDO显示查询结果

Question

I am trying to get the results from a query which should get multiple results and display them all on the page. However it is not displaying any of the content. My guess is a mistake in my syntax for me loop. But I am unsure.

//query to find comments about this map
$query = "
        SELECT 
           user_id,
           comment
         FROM map_comments
         WHERE
           map_id = :mapID
         ";  

//query parameters
$query_params = array(
  ':mapID' => $_SESSION['mapID']
);

try
{
    //execute query
    $statement = $db->prepare($query);
    $result = $statement->execute($query_params);
    //get all results
    $comments = $result->fetchAll;
    if($result === FALSE) 
    { 
      die(mysql_error()); // TODO: better error handling
    }
}
catch(PDOException $e)
{
    die("failed to find comments");
}

foreach($comments as &$comment)
      { 
        echo $comment;
      }

Answer 1

You need parentheses after a function to call it.

$comments = $result->fetchAll;

should be:

$comments = $statement->fetchAll();

Also, the check for if ($result == FALSE) should be before this line. And you can't use mysql_error() if you're using PDO, you should use $statement->errorInfo(). Or you should enable PDO::ERRMODE_EXCEPTION on the connection, and the catch block will be invoked. You should then use $db->errorInfo() in the error message that it prints.