Question

I need to subtract 45 minutes from the date-time variable in PHP.

The code:

$thestime = '2012-07-27 20:40';
$datetime_from = date("Y-m-d h:i",strtotime("-45 minutes",strtotime($thestime)));
echo $datetime_from;

returns the result 2012-07-27 07:55.

It should be 2012-07-27 19:55, though. How do I fix this?

Answer 1

You should do:

$datetime_from = date("Y-m-d H:i", strtotime("-45 minutes", strtotime($thestime)));

Having H instead of h means a 24-hour format is used, representing the hour with leading zeros: 00 through 23.

You can read more on this in the PHP date function documentation.

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There are also object oriented ways of doing this which are more fluent, like DateTime::sub:

$datetime_from = (new DateTime($thestime))->sub(DateInterval::createFromDateString('45 minutes'))->format('Y-m-d H:i')

Or the even more expressive way offered by the Carbon library which extends PHP’s built in DateTime class:

$datetime_from = (new Carbon($thestime))->subMinutes(45)->format('Y-m-d H:i');