$email = $data['add_email'];
    $checkPrevEmail = "SELECT `emails_other` FROM `users` WHERE email='".$email."'";
    $checkQuery = $db->prepare($checkPrevEmail);
    if($checkQuery->execute()) {
        $checkAvailPrevEmail = $checkQuery->fetch(PDO::FETCH_ASSOC);

    if (!empty($checkAvailPrevEmail["emails_other"])) {
            $prevEmail = unserialize($checkAvailPrevEmail["emails_other"]);
            $newEmail = array($email);

            $emailArray = array_merge($prevEmail, $newEmail);
            $emailArray = serialize($emailArray);
        } else {
            $emailArray = array($email);
            $emailArray = serialize($emailArray);
        }

            $sqlUpdate = "UPDATE users SET emails_other='".$emailArray."' WHERE email='".$email."'";
        $query = $db->prepare($sqlUpdate);
        if($query->execute()){
            $res = array(
            "code" => "1",
            "success" => "true",
            "userinfo" => $checkAvailPrevEmail,
            "message" => "Your Email info has been added."
            );
        } else {
            $res = array(
            "code" => "0",
            "success" => "false",
            "userinfo" => "",
            "message" => "Please try again later."
            );
        }