cbk-12.rb

def classes_user_auto ( classes, from, to )
  results = []
  classes.each do | range |
    os = Order.where( :state => :printed.to_s, :created_at => from .. to ).group( :user_id ).having( "count(*) >= #{ range.first } AND count(*) <= #{ range.last }" )
    n = os.count.count
    t = os.sum( :amount_eu ).sum{ | k, v | v }.to_f.round( 2 )
    results << [ "#{ from .. to }", "#{ range }", n, t ]
  end
  results
end
classes = [
      0 .. 1,
      2 .. 3,
      4 .. 6,
      7 .. 10,
      10 .. 10000
]
from = Date.today.beginning_of_year - 1.year
to = Date.today.beginning_of_year
# Usage:
# classes_user_auto( classes, from, to )