Question

A project has 3 tables : client, invoices, deliveries

The relations are:

             client has_many invoices
             client has_many deliveries


              invoices belongs_to client
              deliveries belongs_to client

Both invoices and deliveries model have a date field.

Now I want to find all clients who has at least 1 record either in invoices or deliveries within that month, so that need the distinct clients who have records in invoices or have records in deliveries or even both.

How to find the clients using Rails or even SQL ?

Thanks for help

Answer 1

This would be my first crack at it:

Client.all(:include => [:deliveries, :invoices], :conditions => ['(deliveries.date > :start_date) OR (invoices.date > :start_date)', :start_date => 1.month.ago])

Ideally I would want to use named_scope or custom finder method in the model to handle this:

class Client < ActiveRecord::Base
   named_scope :active_since, lambda {|date| {:include => [:deliveries, :invoices], :conditions => ['(deliveries.date > :start_date) OR (invoices.date > :start_date)', :start_date => date]}}

  # or
  def self.find_by_delivery_or_invoice_activity
    all(:include => [:deliveries, :invoices], :conditions => ['(deliveries.date > :start_date) OR (invoices.date > :start_date)', :start_date => 1.month.ago])
  end
end

I am pretty sure this should be pretty close to what you need, but I wouldn’t expect it to work without some modifications for your situation.