I'm currently trying to do it that way:
// Creating date object
$date = new Zend_Date();
// Adding to it 4 weeks
$date->add('4', Zend_Date::WEEK); // it's expire day
// Getting date in integer(i guess it's unix timestamp yes?)
$date->get();
// Saving it to Mysql in field 'expire' with type Varchar
Then, when needed to get rows, that have date bigger(that haven't yet expired), than current I just add to SQL a simple statement WHERE expire >= $current_date.
Or there is better way to do it? Or how it happens usually?
Thanks for the attention. :)