[#1] vitkor dot kruglikov at gmail dot com [2015-06-15 08:55:14]

It can be unclear for someone how to use this function.
Here is the example:

$date=date_create("2013-03-15");
date_sub($date,date_interval_create_from_date_string("40 days"));
echo date_format($date,"Y-m-d");

[#2] Thomas LEDUC [2015-02-04 11:14:09]

To glue to the OOP, it's better to use it with DateInterval::createFromDateString

<?php 
$dateB = new DateTime('2020-12-20'); 
$dateA = $dateB->sub(DateInterval::createFromDateString('10 days'));
?>

more detail here :
<?php
public static function createFromDateString ($time) {}
?>

[#3] Jonathan Poissant [2011-01-21 07:26:02]

You cannot replace date_sub('2000-01-20') by DateTime::sub('2000-01-20') because DateTime::sub is not static. You have to create the DateTime object first.

Example:

<?php $dateA = date_sub('2000-01-20', date_interval_create_from_date_string('10 days')); ?>

will be replace by
<?php
$dateB = new DateTime('2000-01-20');
$dateA = $dateB->sub(date_interval_create_from_date_string('10 days'));
?>