DateTime::sub

date_sub

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

DateTime::sub -- date_sub — Subtracts an amount of days, months, years, hours, minutes and seconds from a DateTime object

Description

Object-oriented style

public DateTime::sub(DateInterval $interval): DateTime

Procedural style

date_sub(DateTime $object, DateInterval $interval): DateTime

Modifies the specified DateTime object, by subtracting the specified DateInterval object.

Like DateTimeImmutable::sub() but works with DateTime.

The procedural version takes the DateTime object as its first argument.

Parameters

object: Procedural style only: A DateTime object returned by date_create(). The function modifies this object.
interval: A DateInterval object

Return Values

Returns the modified DateTime object for method chaining.

Errors/Exceptions

Object Oriented API only: If an unsupported operation is attempted, such as using a DateInterval object representing relative time specifications such as next weekday, a DateInvalidOperationException is thrown.

Changelog

Version	Description
8.3.0	Now throws a DateInvalidOperationException with DateTime::sub(), instead of a warning when an unsupported operation is attempted. date_sub() has not been changed.

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User Contributed Notes 1 note

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laurent dot payetFORBOTS at FORBOTSsupervan dot fr ¶

1 day ago

Be careful when subtracting a duration crossing a DST change, it can output a resulting date AFTER your base date.

// tested in 8.3.18, 7.4.33

// DST timezone shift is applied properly when setting time explicitely

echo (new DateTime('2025-03-30'))->setTimeZone(new DateTimeZone('Europe/Paris'))->setTime(1,59,0)->format('c').PHP_EOL;
echo (new DateTime('2025-03-30'))->setTimeZone(new DateTimeZone('Europe/Paris'))->setTime(2,0,0)->format('c').PHP_EOL;
echo (new DateTime('2025-03-30'))->setTimeZone(new DateTimeZone('Europe/Paris'))->setTime(2,1,0)->format('c').PHP_EOL;

// 2025-03-30T01:59:00+01:00 < correct
// 2025-03-30T03:00:00+02:00 < correct
// 2025-03-30T03:01:00+02:00 < correct

echo PHP_EOL;

// DST timezone shift is applied properly when addind a duration

$startDateTime = (new DateTime('2025-03-30'))->setTimeZone(new DateTimeZone('Europe/Paris'))->setTime(1,58,0);
echo $startDateTime->format('c').PHP_EOL;
$endDatetime = clone($startDateTime)->add(DateInterval::createFromDateString('4 minutes'));
echo $endDatetime->format('c').PHP_EOL;

// 2025-03-30T01:58:00+01:00 < correct
// 2025-03-30T03:02:00+02:00 < correct

echo PHP_EOL;

// DST timezone shift is applied improperly when subtracting a duration

$startDateTime = (new DateTime('2025-03-30'))->setTimeZone(new DateTimeZone('Europe/Paris'))->setTime(3,2,0);
echo $startDateTime->format('c').PHP_EOL;
$endDatetime = clone($startDateTime)->sub(DateInterval::createFromDateString('4 minutes'));
echo $endDatetime->format('c').PHP_EOL;

// 2025-03-30T03:02:00+02:00 < correct
// 2025-03-30T03:58:00+02:00 < incorrect !!!

echo PHP_EOL;

// DST timezone shift is still applied improperly when adding a negative duration

$startDateTime = (new DateTime('2025-03-30'))->setTimeZone(new DateTimeZone('Europe/Paris'))->setTime(3,2,0);
echo $startDateTime->format('c').PHP_EOL;
$endDatetime = clone($startDateTime)->add(DateInterval::createFromDateString('-4 minutes'));
echo $endDatetime->format('c').PHP_EOL;

// 2025-03-30T03:02:00+02:00 < correct
// 2025-03-30T03:58:00+02:00 < incorrect !!!