How to Subtract Hours to Date and Time in PHP

The following is really easy way to subtract hours in date and time using PHP. Using the date function to set the format of the date to be returned then using strtotime.

The following source code will subtract 2 hours to current date and time.

<?php
    $start = date('Y-m-d H:i:s');
    echo date('Y-m-d H:i:s',strtotime('-2 hour',strtotime($start)));
?>

The following source code will subtract 2 hours to date and time.

<?php
    $start = '2018-05-21 20:24:45';
    echo date('Y-m-d H:i:s',strtotime('-2 hour',strtotime($start)));
?>