php-mysqlは現在の日付をさらに日数挿入します

こんにちは私はこの問題を抱えており、DATE_ADDで見つけたすべての解決策を試しました。これが私のコードです。

 $create_time = date("Y-m-d H:i:s");
if (md5($_POST['norobot']) == $_SESSION['randomnr2'])   
{ 
    if ((strlen($usern) >= 5) && (strlen($pass) >= 5)&&(strlen($email) >= 12)&&(strlen($idcard)==7))
    {
        $usr = mysql_query("Select * from account.account where login='$usern'");
        $ema = mysql_query("Select * from account.account where email='$email'");

        if ((mysql_num_rows($usr)==1)|| (mysql_num_rows($ema)==1))
        {
            echo error("Cont sau email utilizate.Incercati altele sau click <a href='index.php?page=recuperare-pw'>aici</a> pentru recuperare parola.");
        }
        else
        {   
            if ($_POST['read'] == "checked")
            {
                $rand = rand(99999,9999999999);
                $cod_activ = md5($rand);
                //$cod_activ= "1";
                mysql_query("Insert into account.account (Login,Password,Real_name,Social_id,Email,status,create_time,gold_expire,silver_expire,safebox_expire,autoloot_expire,fish_mind_expire,marriage_fast_expire,money_drop_rate_expire,coins,web_aktiviert) values('$usern',password('$pass'),'$name','$idcard','$email','OK','$create_time','2022-12-31 12:00:00','2022-12-31 12:00:00','2022-12-31 12:00:00','2022-12-31 12:00:00','2022-12-31 12:00:00','2022-12-31 12:00:00','2022-12-31 12:00:00','0','$cod_activ')") or die(mysql_error());
                echo succes('Cont creat cu succes.Va puteti loga acum!');
 Copy code

2022-12-31 12:00:00の代わりに現在の日付+30日を追加したいのですが。アイデアが足りません。