ActiveRecord Group Count

Installing

Add it to your project's Gemfile

gem "active_record_group_count"

and run

bundle install

Description

When you do group in Rails (SQL GROUP BY), count will return an ActiveSupport::OrderedHash. Sometimes you want the sum count (count of all the results, not by group). You can do count.keys.count, however this has serious performance issues if you have a lot of groups in the results.

I wrote an ActiveRecord scope that will override the count method to perform a more optimised count query (of course it will now return a FixNum instead of a Hash). You can use this in combination with Kaminari and get much more efficient calculation of total_pages and total_count.

Use

Just use the returns_count_sum scope before calling count:

MyModel.group(:something).returns_count_sum.count

You can use it with Kaminari too (it's much faster):

MyModel.group(:something).returns_count_sum.page(1).per(10).total_pages

Tests

I've tested this project using RSpec.

You can run the tests by running

rake spec

in the root directory of this gem (so you have to clone it first).

Problems

If you have problems open an issue here on Github.

License

This project rocks and uses MIT-LICENSE.