Rails find_by option syntax for last record

Question

It's probably unrelated to the issue, but for context I'm using the devise_invitable gem in my app. I've started to modify the invitations_controller.rb as I want to save additional associations between the invited_user and other models in my app.

I think the root of my issue is that an inviting_user can invite multiple other users and each of these associations is saved in the User model with a field called invited_by_id

Before making the additional desired associations between the invited_user and my other models, I retrieve the invited_user's id with the following:

@invited_user = User.find_by_invited_by_id(current_inviter)

This does successfully retrieve a record from the User table, but it appears to be the first user invited by the current_inviter.

I'd like to change the logic so it retrieves the last user invited by the current_inviter. As such, I tried:

@invited_user = User.find_by_invited_by_id(:last, current_inviter)

But unfortunately that returns the following error:

NoMethodError: undefined method `empty?' for 1:Fixnum

Any assistance is appreciated. Thank you.

Answer 1

You can use the following (Rails 3):

User.where(invited_by_id: current_inviter).last

Or use the old syntax (Rails 2):

User.find(:last, :conditions => ['invited_by_id = ?', current_inviter])