Question

I am new to Rail and trying to make a query in ActiveRecord. I am trying to get all of the records with the status of ‘Landed’, that are over 60 days old. My query works up to the point of getting all of the projects with the status of ‘Landed’. When I add in the last condition of “created_at < ? “, then I always get an empty relation. I know that I have projects that fit that description, so I am doing something wrong in my query and dont understand. I believe my error is in the date comparison, but I am not sure.

1. Projects
    belongs_to :status
    has_many :project_status_histories
2. Status
    has_many :projects
    has_many :project_status_histories
3. Project_Status_Histories
    belongs_to :status
    belongs_to :project

Project.find(:all, :joins => [:project_status_histories, :status], :conditions => {:projects => {:status_id => Status.where(:name => 'Landed').first.id }, :project_status_histories => {:created_at => ["created_at < ?", (Date.today - 60.days)]}})

I have tried to build the query, step by step, with the dbconsole and am not having any luck. Thanks for all the help in advance.

Answer 1

I don’t think it’s the date arithmetic. One nice way to do this would be with named scopes. Add the following to project.rb:

scope :landed, joins(:status).where('statuses.name' => 'Landed')
scope :recent, lambda \
              { joins(:project_status_histories) \
              .where('project_status_histories.created_at < ?', Date.today - 60.days) } 

Then you can retrieve the relevant records/objects with:

Project.landed.recent

This worked for me in my test. You should also check out the rails guide, from which I stole most of this:

http://guides.rubyonrails.org/active_record_querying.html#scopes