使用PDO从MySQL获得结果(Get results from from MySQL using PDO)

 我正在尝试使用PDO从我的表中检索数据，只是我似乎无法向浏览器输出任何内容，我只是得到一个纯白页。 
 
try {
  // Connect and create the PDO object
  $conn = new PDO("mysql:host=$hostdb; dbname=$namedb", $userdb, $passdb);
  $conn->exec("SET CHARACTER SET utf8");      // Sets encoding UTF-8

        $lastIndex = 2;

        $sql = "SELECT * FROM directory WHERE id > :lastIndex AND user_active != '' LIMIT 20"
        $sth = $conn->prepare($sql);
        $sth->execute(array(':lastIndex' => $lastIndex));

        $c = 1;
        while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
            echo 'ALL STYLING ETC RESULTS HERE';
        $c++;
        }

  $conn = null;        // Disconnect
}

I'm trying to retrieve data from my table using PDO, only I can't seem to output anything to my browser, I just get a plain white page.
 
try {
  // Connect and create the PDO object
  $conn = new PDO("mysql:host=$hostdb; dbname=$namedb", $userdb, $passdb);
  $conn->exec("SET CHARACTER SET utf8");      // Sets encoding UTF-8

        $lastIndex = 2;

        $sql = "SELECT * FROM directory WHERE id > :lastIndex AND user_active != '' LIMIT 20"
        $sth = $conn->prepare($sql);
        $sth->execute(array(':lastIndex' => $lastIndex));

        $c = 1;
        while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
            echo 'ALL STYLING ETC RESULTS HERE';
        $c++;
        }

  $conn = null;        // Disconnect
}

原文：