I have these dates and times:
schedule.day_start # => 2014-09-27 15:30:00 UTC date_now = Time.now # => 2014-09-27 15:11:14 +0200 date_now + 60.minutes # => 2014-09-27 16:11:14 +0200 I am trying to detect all schedules that start 60 minutes or less before day_start. With the following code, I get as a response "NO" instead of "YES".
if schedule.day_start < (Time.now + 60.minutes) "YES" else "NO" end Why is 2014-09-27 15:30:00 UTC bigger than 2014-09-27 16:11:14 +0200?
Work them dates as UTC, so you will avoid time zone problems
if schedule.day_start.utc < (Time.now + 60.minutes).utc ... 
Time.now.utc shows me 2014-09-27 14:10:14 UTC, but the current time is 2014-09-27 16:10:14 UTC. How to compare these two dates then? (schedule.day_start shows the "correct" date - not -2 hours)
Time.now? Because if for example it is assigned to a constant or a global variable it could have record the time when you started your server. Also check if you correctly set-up your config.time_zone, and off course if your system is on the right time with ntpdateBecause
2014-09-27 16:11:14 +0200 is simultaneous to
2014-09-27 14:11:14 UTC which comes before
2014-09-27 15:30:00 UTC With Time objects, "follows" translates to "greater".
With Time objects, "follows" translates to "greater".?
A comes after (i.e. follows) time B on the temporal scale, then code A > B in Ruby would be true (i.e., A is greater than B).Anywhere, if time A comes after time B, then A is considered to be greater than B. The same is in your case.
schedule.day_start # => 2014-09-27 15:30:00 UTC
date_now + 60.minutes # => 2014-09-27 16:11:14 +0200 which is 2014-09-27 14:11:14 UTC.
Here, you can clearly see that, Time.now + 60.minutes is a timestamp before schedule.day_start. Thus, schedule.day_start is greater than Time.now + 60.minutes, that's why your "if" case doesn't hold true and hence NO is printed.
Rememeber your result is false because the GMT, to resolve this and compare the only datetime without GMT using UTC, try this:
minutes = 60.minutes t1 = Time.at(schedule.day_start.utc).to_datetime t2 = Time.at((Time.now + minutes).utc).to_datetime if t1 < t2 "YES" else "NO" end 