RoR: Counting records from day while querying datetime

I'm trying to create a loop for the last 15 days to give me counts of records on each day.

So @records should be an array of counts for the last 15 days.

However, the record stores dates as datetime (as you know), and I'm trying to reference any time within a single day.

@records = []

      15.times do |i|
        bar =  Records开发者_StackOverflow.all.count( 
          :type => 'large',
          :created_at => ((i-1).days.ago..i.days.ago)
          )
        @records << bar
      end

Thoughts? Thanks!

---

Record.where("date(created_at) > ?", 15.days.ago).group("date(created_at)").count

should give records count by days.

Sample Output:

 {"2011-07-02"=>4,
 "2011-07-04"=>5,
 "2011-07-05"=>16,
 "2011-07-06"=>12,
 "2011-07-11"=>19}

---

You can use SQL to do the count without instantiating a lot of Record objects (which uses memory/time)

ActiveRecord::Base.connection.select_rows('SELECT DATE(created_at) AS d, COUNT(*) AS c FROM my_records_table GROUP BY DATE(created_at)')

This will give you an array of arrays:

> pp ActiveRecord::Base.connection.select_rows('SELECT DATE(created_at) AS d, COUNT(*) AS c FROM my_records_table GROUP BY DATE(created_at)')
[["2011-06-23", "326"],
 ["2011-06-24", "337"],
 ["2011-06-25", "334"],
 ["2011-06-26", "353"],
 ["2011-06-27", "210"],
 ["2011-06-28", "330"],
 ["2011-06-29", "331"],
 ["2011-06-30", "338"],
 ["2011-07-01", "335"],
 ["2011-07-02", "366"],
 ["2011-07-03", "320"],
 ["2011-07-04", "338"],
 ["2011-07-05", "338"],
 ["2011-07-06", "299"],
 ["2011-07-07", "326"],
 ["2011-07-08", "314"],
 ["2011-07-09", "331"],
 ["2011-07-10", "335"],

...but I just saw dexter's answer and that is WAY better :)