Are PHP DateInterval comparable like DateTime?

Question

I discovered that a DateTime object in PHP can be compared to another as the \">\" and \"<\" operators are overloaded.

Is it the same with DateInterval?

A

Answer 1

In short, comparing of DateInterval objects is not currently supported by default (as of php 5.6).

As you already know, the DateTime Objects are comparable.

A way to achieve the desired result, is to subtract or add the DateInterval from a DateTime object and compare the two to determine the difference.

Example: https://3v4l.org/kjJPg

$buildDate = new DateTime('2012-02-15');
$releaseDate = clone $buildDate;
$releaseDate->setDate(2012, 2, 14);
$buildDate->add(new DateInterval('P15D'));

var_dump($releaseDate < $buildDate); //bool(true)

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Edit

As of the release of PHP 7.1 the results are different than with PHP 5.x, due to the added support for microseconds.

Example: https://3v4l.org/rCigC

$a = new \DateTime;
$b = new \DateTime;

var_dump($a < $b);

Results (7.1+):

bool(true)

Results (5.x - 7.0.x, 7.1.3):

bool(false)

To circumvent this behavior, it is recommended that you use clone to compare the DateTime objects instead.

Example: https://3v4l.org/CSpV8

$a = new \DateTime;
$b = clone $a;
var_dump($a < $b);

Results (5.x - 7.x):

bool(false)