methodology comparison

past_orders.rb

def find_suggestions_for(restaurant)
  past_orders = []
  orders.each {|o| past_orders << o if o.restaurant == restaurant }
  past_orders
end


def find_suggestions_for(restaurant)
  orders.inject([]) do |result, order|
    result << order if order.restaurant == restaurant
    result
  end
end

def find_suggestions_for(restaurant)
  orders.select {|o| o.restaurant == restaurant} 
end

def find_suggestions_for(restaurant)
  orders.joins(:meal).where('meals.restaurant_id' => restaurant.id)
end