$statement = $conn->prepare(
    "UPDATE
        authors
    SET IPAddr = :ip
    WHERE company_url = :companyurl");

    foreach ($conn->query($sql) as $row) {
        if ($row['company_url'] != "") {
            $hostname = $row['company_url'];
            $ip = gethostbyname($hostname);
            $statement->bindParam(':ip', $ip);
            $statement->bindParam(':companyurl', $hostname);
            $statement->execute();
        }
    }