ActiveRecord Select with Parameter Binding

activerecord, ruby-on-rails

Solution

You can use one of the `ActiveRecord::Sanitization` class methods.

These are mixed into `ActiveRecord::Base` and are almost all protected so they are most easily accessed by defining a class method on your model:

class User < ActiveRecord::Base
  def self.select_with_args(sql, args)
    query = sanitize_sql_array([sql, args].flatten)
    select(query)
  end
end

It's also worth looking for other ways to fetch your data and comparing their performance to the subquery method. For example, you could fetch the subscription counts with a separate query:

subs_by_user = Subscription.group(:user_id).where('created_at < ?', d).count()

Problem

I want to use a subquery with ActiveRecord like so: ``` User.select( 'users.*, (select sum(amount) from subscriptions where subscriptions.user_id = user.id and created_at < ? ) as amt)' ).order('amt') ``` However, on the second to last line, I have the problem that I can't figure out how to bind the `Time` class parameter, as `ActiveRecord::Base`'s `select` method doesn't accept more than one parameter (the sql string). What do I do?

Original source