在Rails的上下文中，如何在第二秒之前对列进行排序？

Question

I am working with rails and postgresql. I have a created_at timestamp on a model. I am in a situation where I need to order the results by second. I can't seem to get rails todo this.

eg If I insert 5 records in 1 minute, and then want to sort by created_at time, since they all have the same minute, it starts to order them by alpha because they all have the same insert minute.

How can I make it so that it orders by the insert in seconds. Postgres is storing it. But DateTime doesn't seem to take seconds into account in this way...

I hope this makes sense

Kirk

Answer 1

ActiveRecord order method should sort including the second

Eg:

Note the last two datetimes are in the same minute

User.pluck(:created_at)
=> [Fri, 14 Mar 2014 16:26:02 UTC +00:00, Fri, 14 Mar 2014 18:33:42 UTC +00:00, Fri, 14 Mar 2014 18:33:51 UTC +00:00]

User.order("created_at desc").collect(&:created_at)
 => [Fri, 14 Mar 2014 18:33:51 UTC +00:00, Fri, 14 Mar 2014 18:33:42 UTC +00:00, Fri, 14 Mar 2014 16:26:02 UTC +00:00]

Answer 2

Adding:

default_scope -> { order('created_at DESC') }

to your ActiveRecord should do it because created_at should look like this:"2014-03-12 15:29:26" which specifies the seconds.