ActiveRecord Select with Parameter Binding

Question

I want to use a subquery with ActiveRecord like so:

User.select(
    \'users.*, 
    (select sum(amount) 
        from subscriptions 
        where subscript         


        

Answer 1

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()