lirenyeo

require 'prawn'


arr = HallSession
        .joins(:check_in_sessions, :hall)
        .group('check_in_sessions.hall_session_id, auditorium_halls.name, hall_sessions.start_at, hall_sessions.end_at, hall_sessions.id')
        .select('auditorium_halls.name as hall_name, hall_sessions.start_at, hall_sessions.end_at, COUNT(*) as c')
        .order('hall_name, start_at, end_at')
        .map do |ci|
          [