Модель, например

controller.rb

if params[:date]
  @date = Date._strptime(params[:date], '%m-%Y')
  unless Date.today.month == @date[:mon] && Date.today.year == @date[:year]
    @showings = Showing.by_date(@date)
  end
end

model.rb

class Showing < ActiveRecord::Base
  def self.last
    find_by_sql("SELECT * FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings);")
  end

  def self.dashboard
    find_by_sql("(SELECT title, value, format FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings)
                     AND title = 'ФОТ сотрудников'
                 LIMIT 1)
                 UNION ALL
                 (SELECT title, value, format FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings)
                     AND title = 'Количество сотрудников'
                 LIMIT 1)
                 UNION ALL
                 (SELECT title, value, format FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings)
                     AND title = 'Остаток на счетах'
                 LIMIT 1)
                ;")
  end
  
  def self.history
    find_by_sql(
        "(SELECT title, value, format FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings)
                     AND title != 'ФОТ сотрудников'
                     AND title != 'Количество сотрудников'
                     AND title != 'Остаток на счетах'
                     AND title != 'Итого')
         UNION ALL
         (SELECT title, value, format FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings)
                     AND title = 'Итого'
         LIMIT 1)
        ;"
    )
  end

  def self.by_date(date)
    find_by_sql(
        "(SELECT title, value, format FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings
                        WHERE extract(month from date) = #{date[:mon]} AND extract(year from date) = #{date[:year]})
                     AND title != 'ФОТ сотрудников'
                     AND title != 'Количество сотрудников'
                     AND title != 'Остаток на счетах'
                     AND title != 'Итого')
         UNION ALL
         (SELECT title, value, format FROM showings WHERE date_trunc('hour', created_at) =
                     (SELECT date_trunc('hour', MAX(created_at)) FROM showings
                        WHERE extract(month from date) = #{date[:mon]} AND extract(year from date) = #{date[:year]})
                     AND title = 'Итого'
         LIMIT 1)
        ;"
    )
  end
end