Question

I am trying to create a array that should be something like this:

[ [created_at date * 1000, count record for that date],
  [created_at date * 1000, count record for that date], 
  [created_at date * 1000, count record for that date] ]

The created_at date is not exactly the same, because of minutes, hours and seconds.
I was thinking is it possible to change created_at time on create to 00:00:00

I have tried with this,

@kliks = Klik.all.map{|klik| [(klik.created_at.to_i * 1000), 1]}

But I have not figure out to sum those records that are created the same day. Also this loops create a array for every single record, I don’t want duplicates of the sum.

Answer 1

Rails has ActiveRecord::Calculations which is designed to do exactly this sort of thing at the database level. You should use it. In this case, count is the method you want:

@kliks = Klik.count( :group => "DATE( created_at )" )

This is equivalent to the following SQL:

SELECT *, COUNT(*) FROM kliks
GROUP BY DATE( created_at )

The DATE() function is MySQL changes a datetime (like created_at, e.g. 2012-02-27 10:08:59) to a plain date (e.g. 2012-02-27). No need to go converting things to integers or multiplying minutes and seconds, and no need to use map or any other method in Ruby.