Gmdate() - want 1 hr before time

Hi,
I am using php gmdate().
Now I am entering all dates in my dbase using gmdate("Y-m-d H:i:s")
I want 1 hr before datetime.
So am using like
gmdate("Y-m-d H:i:s", mktime(gmdate("H")-$hrs, gmdate("i"), gmdate("s"), gmdate("m"), gmdate("d"), gmdate("Y")));
where $hr = 1
When I echo current date i,e

$date = gmdate('Y-m-d H:i:s');
echo "<br/>current date is $date";

its
2009-12-27 03:54:08

and when echo my code of getting 1 hr before
$date1 = gmdate("Y-m-d H:i:s", mktime(gmdate("H")-1, gmdate("i"), gmdate("s"), gmdate("m"), gmdate("d"), gmdate("Y")));

its
2009-12-26 02:54:08

difference between these 2 days is 1 day and not 1 hr.
I want 1 hr before datetime to be
2009-12-27 02:54:08

Can please anybody help.
Thanks in advance
Regards

 

Untested, but worth to try

<?php
$format = "Y-m-d H:i:s";
$now = time();
$adjusted_time = $now - 3600;// 3600 seconds before now

$date = gmdate($format, $adjusted_time);

echo $date;
?>

PHP: