Excepción no detectada DOP

Question

Este error aparece cuando se ejecuta el código de abajo:

Fatal error: Uncaught exception 'PDOException' with message 
  'SQLSTATE[42000]: Syntax error or access violation: 1065 Query was empty'
  in /home/content/63/6563663/html/inventory/pg.php:20
Stack trace:
  #0 /home/content/63/6563663/html/inventory/pg.php(20): PDOStatement->execute()
  #1 {main} thrown in /home/content/63/6563663/html/inventory/pg.php on line 20

<?php

$u=$_GET["u"];


if ((isset($_POST["MM_update"])) && ($_POST["MM_update"] == "form2")) {
$amount = isset($_POST['amount']) ? $_POST['amount'] : null;
if (null != $amount) {

$user = 'username';
$pass = 'password';
$pdo = new PDO('mysql:host=localhost', $user, $pass);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
session_start();
$tablename = $_SESSION['MM_Username'];
$query = sprintf("UPDATE `%s` SET `stock` = :amount WHERE `itemname` = :u ", $tablename);
$stmt = $pdo->prepare($query);
$stmt->bindParam('amount', $amount);
$stmt->execute();
}
}

?>

Las obras pero ahora con este error. Me disculpo como yo soy nuevo en DOP.

Fatal error: Uncaught exception 'PDOException' with message
  'SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens'
  in /home/content/63/6563663/html/inventory/pg.php:20
Stack trace:
  #0 /home/content/63/6563663/html/inventory/pg.php(20): PDOStatement->execute()
  #1 {main} thrown in /home/content/63/6563663/html/inventory/pg.php on line 20

Answer 1

Probablemente debería familiarizarse con trying y catching excepciones .

Answer 2

Bueno, el mensaje de error es bastante claro:

  

1.065 consultas estaba vacía

se utiliza el $UpdateQuery variable, que no existe. Probablemente quería decir

 $stmt = $pdo->prepare($query);