插入PDO Php - 错误SQLSTATE [HY000]：一般错误 -

Question

当我运行这个php文件时，显示错误SQLSTATE [HY000]: General error。为什么呢？

function Gethotspots($db) {
    $regId = $_GET['regId'];
    $sql = $db->prepare("INSERT INTO notificaciones (regId) VALUES ('" . $regId . "')");
    $sql->execute();

    $i = 0;

    $pois = $sql->fetchAll(PDO::FETCH_ASSOC);

    if (empty($pois)) {
        $response["productos"] = array();
    }
    else {
        foreach ($pois as $poi) {
            $poi["actions"] = array();

            $response["productos"][$i] = $poi;
            $i++;
        }
    }
    return $response["productos"];
}

$dbhost = "localhost";
$dbdata = "anuncios";
$dbuser = "root";
$dbpass = "";

try {
    $db = new PDO("mysql:host=$dbhost; dbname=$dbdata", $dbuser, $dbpass, array(
            PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));

    $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $response = array();

    $response["productos"] = Gethotspots($db);

    if (empty($response["productos"])) {
        $response["errorCode"] = 20;
        $response["errorString"] = "Ningun producto encontrado.";
    } // if
    else {
        $response["errorCode"] = 0;
        $response["errorString"] = "Todo correcto";
    }

    $jsonresponse = json_encode($response);
    header('Access-Control-Allow-Origin: *');

    echo $jsonresponse;

    $db = null;
} catch (PDOException $e) {
    echo $e->getMessage();
}

全部谢谢！