令和元年/ 2019-12-16 07:17
PHP, 日付, 計算, date, 2019.07.22

$ php -r '$t=time()+(86400*6);echo date("Ymd", $t);'
20190728

~~~~

$mktime = mktime($hour, $min, 0, $m, $d, $y);
$mktime += 86400; //1日の秒数
$m = date("m", $mktime);
$d = date("d", $mktime);
$w = date("w", $mktime);

# 2日後
$mktime = mktime();
$mktime += 86400*2;
$m2 = date("m", $mktime);
$d2 = date("d", $mktime);



Thanks.
mktime
http://php.net/manual/ja/function.mktime.php