gistfile1.rb

class Clinical < ActiveRecord::Base

  # ... snip rest of model...

  def self.income_by_month
    select( 'YEAR(transactiondate) as year, MONTH(transactiondate) as month, SUM(LineBalance) as income' )
      .where(:payment => 0 )
      .where('LineBalance <> 0' )
      .where('analysiscode <> 213' )
      .group(:monthyear)
  end
end