how to get time difference in minutes in rails for two date time fields?

Question

i want to calculate time difference in minutes between two date_time fields.like created_at and updated_at kind of fields. i want the result like this updated_at - created_at = some minutes.

these times are present in time zone of INDIA. how can i do that in rails?

created = article.created_at
updated = article.updated_at

minutes = updated - created

Answer 1

This solution works for ActiveRecord models using TimeWithZone classes for created_at and updated_at.

created = article.created_at
updated = article.updated_at

minutes = (updated - created) / 1.minutes

Answer 2

As created_at and updated_at are of type DateTime, this should work.

created = article.created_at
updated = article.updated_at
minutes = ((updated - created) * 24 * 60).to_i

Explanation:

Subtracting two DateTimes returns the elapsed time in days. In the below example e-d will return (28807336643183/28800000000000). So to convert this into minutes, we need to multiply it by 24*60(As the day has 24 hours and each hour has 60 minutes)

Example(tested):

d = DateTime.now
 => Tue, 13 Jun 2017 10:21:59 +0530 
2.3.3 :003 > e = DateTime.now + 1.day
 => Wed, 14 Jun 2017 10:22:21 +0530
g = ((e-d) * 24 * 60).to_i
 => 1440