How do I use the time function in Views Math expression? I'm having trouble with the Global: Math Expression in a View.  I have an entity type which is a student.  I'd like the student grade level to change automatically from year to year, so I'm storing a graduation year and would like to display grade level by a Math expression.  To do so, I need to include a current time element (month and year).  I have read that time() is useable, but I can't get it to work.  Perhaps I'm using the wrong format in the Expression box under Configure field?  As a test, I put in just time(), but I get a zero at the output.  Is time() useable within Views Math Expressions or do I have to abandon that approach and learn to use the Computed Field module?  If time() is useable, would I be able to convert seconds to years by getting an integer value for time()/60/60/24/365.25 or does is there no integer conversion function here?
If you are using the Views PHP Field, http://drupal.org/project/views_php, you can enter in custom php field information. I would take the original date variable and subtract the date as of now to get the value you want:

  //Just creating a random freshman grad date

  $graduation_year = (date('Y-m-d', strtotime('+4 year')));

  $now = (date ('Y-m-d', (strtotime('now'))));

  $diff = abs($graduation_year - $now);


Based on the absolute difference in years you can do validation in your views field that validates this information and sets the student as a freshman, sophmore, junior or senior (assuming highschool :) ) based on the $diff value of 1,2,3,4. 

That validation would look like:

if ($diff == 1) {
print('Senior');
}
elseif($diff == 2){
print('Junior');
}
elseif($diff == 3){
print('Sophmore');
}
elseif($diff == 4){
print('Freshman');
}


I didn't put exception handling but you get the idea.