def calculate(conn, %{"date_from" => date_from, "date_to" => date_to}) do

revenue = Repo.one(from p in Order, where: p.created_date >= ^date_from and p.created_date <= ^date_to, select: sum(p.paied))
order = Repo.one(from p in Order, where: p.created_date >= ^date_from and p.created_date <= ^date_to, select: count(p.id))
render conn, "statistics.json", %{revenue: revenue, order: order}

end

def render("statistics.json", %{order: order, revenue: revenue}) do

%{
  order: order

}

%{
  revenue: revenue
}

end