Queries to find certain sets of nonprofits

lib/query/query_nonprofits.rb

@@ -101,4 +101,17 @@ module QueryNonprofits
 
      return expr.execute
   end
+
+  def self.find_nonprofits_with_no_payments()
+    Nonprofit.includes(:payments).where('payments.nonprofit_id IS NULL')
+  end
+
+  def self.find_nonprofits_with_payments_in_last_n_days(days)
+    Payment.where("date >= ?", Time.now - days.days).pluck('nonprofit_id').to_a.uniq
+  end
+
+  def self.find_nonprofits_with_payments_but_not_in_last_n_days(days)
+    recent_nonprofits = find_nonprofits_with_payments_in_last_n_days(days)
+    Payment.where("date < ?", Time.now - days.days).pluck('nonprofit_id').to_a.uniq.select{|i| !recent_nonprofits.include?(i)}
+  end
 end