opos_statistiken.rb

stats = []
(Date.parse('2012-09-01') .. Date.today).select{|d| d.day === 1}.map{|erster| erster - 1.month .. erster}.each do |range|
  Invoice.state_machine.states.map(&:name).each do |state|
    rechnungen = Invoice.where(:created_at => range, :state => state.to_s)
    bestellungen = rechnungen.map(&:order_cart)
    stats << [range.first.strftime("%m.%Y"), state.to_s, rechnungen.count, ActionController::Base.helpers.number_with_precision(bestellungen.sum(&:final_amount).to_f, :precision => 2)]
  end
end
stats