Rails Where vs Join vs Union - ruby-on-rails

Question

Having trouble with my activerecord searches. I thought I had my models setup correctly, but I’m poor with my joins (not sure if a join or union is the correct way to go? It shouldn’t be this difficult).
I have guides creating bids on trips that have start_dates. I want to create a list of bids that have expired (ie. the start date is in the past). Guides can also have LosingBids if a bid has been declined
In a perfect world I would have one resultset that includes both losing bids and expired bids for that guide, but I’m find with 2 different result sets. Unfortunately I can’t get any of the “expired bids” to work. Results/errors in the comments of the code.
class GuidesController < ApplicationController
def expired_declined
#this declined_bids call works
#declined_bids = LosingBid.where("guide_id = ?", current_guide.id.to_s)
#this expired_bids call returns Trips, not Bids
#expired_bids = Bid.where("guide_id = ?", current_guide.id.to_s).expired
#this expired_bids call gives me the following error:
#SQLite3::SQLException: no such column: trips.start_date: SELECT 1 AS one FROM #”bids" WHERE (guide_id = '1') AND (trips.start_date < '2018-05-30') LIMIT ?
#expired_bids = Bid.where("guide_id = ?", current_guide.id.to_s).where("trips.start_date < ?", Date.today)
end
end
class Guide < ApplicationRecord
has_many :bids
has_many :losing_bids
end
class Trip < ApplicationRecord
has_many :bids
end
class Bid < ApplicationRecord
belongs_to :trip
belongs_to :guide
def self.expired
Trip.where("start_date <= ?", Date.today) #.where("guide_id = ?", current_guide.id.to_s)
end
end
class LosingBid < ApplicationRecord
belongs_to :trip
belongs_to :guide
end

Answer 1

Trip.where("start_date <= ?", Date.today).bids will return you the expired bids.
You should move the expired scope in the Trip, rather than on the Bid.
If you want a scope on Bid you can define.
class Bid
scope :expired, -> { joins(:trip).where('trips.start_date <= ?', Date.current) }
end

Answer 2

I would really question if you need to have a separate LosingBid model or if its just creating duplication and unnecessary complexity. Instead just add an enum column to bids which contains the status:
class Bid
enum status: [:pending, :declined, :expired, :accepted]
end
This is just a simple integer column that acts as a bit mask.
This will simply let you query by:
Bid.pending
Bid.expired
Bid.where(status: [:pending, :accepted])
Bid.where.not(status: :accepted)
You can simply reject a bid by:
class BidsController
# PATCH /bids/decline
def reject
#bid.declined!
redirect_to bid, notice: 'Bid declined'
end
end
You could then setup scheduled task which runs once per day to automatically expire tasks (example with the whenever gem):
every 1.days do
runner "BidExpiryService.perform"
end
# app/services/bid_expiry_service.rb
module BidExpiryService
def self.perform
bids = Bid.pending
.joins(:trip)
.where('trips.start_date <= ?', Date.current)
bids.update_all(status: Bid.statuses[:expired])
# #todo notify guides that bid has expired
end
end