Date minus 1 year?

Question

I\'ve got a date in this format:

2009-01-01

How do I return the same date but 1 year earlier?

Answer 1

Using the DateTime object...

$time = new DateTime('2099-01-01');
$newtime = $time->modify('-1 year')->format('Y-m-d');

Or using now for today

$time = new DateTime('now');
$newtime = $time->modify('-1 year')->format('Y-m-d');

Answer 2

On my website, to check if registering people is 18 years old, I simply used the following :

$legalAge = date('Y-m-d', strtotime('-18 year'));

After, only compare the the two dates.

Hope it could help someone.