PHP 데이터베이스 쿼리에서 \'bool 유형 값의 배열 오프셋에 액세스하는 중\' 오류를 방지하는 방법은 무엇입니까?

$emailRes = $query->fetch(PDO::FETCH_ASSOC);
if ($emailRes) {
    // Use $emailRes
}

$emailRes = $query->fetch(PDO::FETCH_ASSOC);
$email = $emailRes['Email'] ?? ''; // Default: empty string

$query = $pdo->prepare("SELECT COUNT(*) FROM Users WHERE Username =:Username");
$query->execute([':Username' => $name]);
if ($query->fetchColumn()) {
    throw new \Exception("Username is already in use!");
}

$query = $pdo->prepare("SELECT COUNT(*) FROM Users WHERE Email =:Email");
$query->execute([':Email' => $email]);
if ($query->fetchColumn()) {
    throw new \Exception("Email is already in use!");
}

$query = $pdo->prepare("SELECT COUNT(*) FROM Users WHERE Username =:Username OR  Email =:Email");
$query->execute([':Username' => $name, ':Email' => $email]);
if ($query->fetchColumn()) {
    throw new \Exception("Username or email is already in use!");
}