Counting Members Based on Invitations - Query - ruby-on-rails

Question

I am counting many user generated actions and for the most part it's easy, but with regard to one, more complex query, I am having trouble.
I have an invitations model and a user model and I can easily count the number of invitations the user sent, but I want to count the number of new members that signed up based on the invitations the existing member sent out.
In invitations, the invitees email is saved as recipient_email
Then, I know I can check that against new members email some how, but am not clear on the syntax.
Any help will be greatly appreciated. More information below.
Invitation Model:
class Invitation < ActiveRecord::Base
attr_accessible :recipient_email, :sender_id, :sent_at, :token
belongs_to :sender, :class_name => 'User'
has_one :recipient, :class_name => 'User'
validates_presence_of :recipient_email
validates_uniqueness_of :recipient_email, :message => '%{value} has already been invited'
validate :recipient_is_not_registered
validate :sender_has_invitations, :if => :sender
default_scope order: 'invitations.created_at DESC'
before_create :generate_token
before_create :decrement_sender_count, :if => :sender
after_create do |invitation|
InvitationMailer.delay.invitation_email(self)
end
def invitee
User.find_by_email(self.recipient_email)
end
def invitee_registered?
!invitee.blank?
end
def invitee_submitted?
!invitee.try(:submissions).blank?
end
private
def recipient_is_not_registered
errors.add :recipient_email, 'is already registered' if User.find_by_email(recipient_email)
end
def sender_has_invitations
unless sender.invitation_limit > 0
errors.add_to_base "You have reached your limit of invitations to send.
You can contact Lumeo if you'd like to request more."
end
end
def generate_token
self.token = Digest::SHA1.hexdigest([Time.now, rand].join)
end
def decrement_sender_count
sender.decrement! :invitation_limit
end
end
User Model:
class User < ActiveRecord::Base
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable, :mailchimp
attr_accessible :name, :email, :password, :password_confirmation,
:remember_me, :role_id, :role_ids, :image_attributes,
:terms, :profile_attributes, :current, :image, :roles,
:invitation_token, :join_mailing_list, :affiliate_id,
:invitation_affiliate_token, :affiliation, :referrer_id
validates_uniqueness_of :email
VALID_NAME_REGEX = /[\w]+([\s]+[\w]+){1}+/
validates :name, presence: true,
format: {with: VALID_NAME_REGEX}
#invitation
has_many :sent_invitations, :class_name => 'Invitation', :foreign_key => 'sender_id'
belongs_to :invitation
def invitation_token
invitation.token if invitation
end
def invitation_token=(token)
self.invitation = Invitation.find_by_token(token)
end
before_create :set_invitation_limit
has_one :invitation_affiliate, :class_name => "Affiliate", :foreign_key => 'token', :primary_key => 'invitation_affiliate_token'
private
def set_invitation_limit
self.invitation_limit = 100
end
end
Invitation and User Tables:
create_table "users", :force => true do |t|
t.string "email", :default => "", :null => false
t.string "encrypted_password", :default => "", :null => false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", :default => 0
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.integer "role_id"
t.string "name"
t.integer "invitation_id"
t.integer "invitation_limit"
end
create_table "invitations", :force => true do |t|
t.integer "sender_id"
t.string "recipient_email"
t.string "token"
t.datetime "sent_at"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end

Answer 1

I could think of two different ways:
Add accepted field in invitations
You could add a boolean field for invitations named accepted, the default value will be false and you set it to true when the receipent accepts the invitation. Then you create a scope named accepted that returns only accepted invitations
scope :accepted, where(accepted: true)
You get what you want by #user.sent_invitations.accepted.count
2 . Do the following query
User.where(email: #user.sent_invitations.map(&:recipient_email)).count