test sum

app/models/cash_balance.rb

@@ -42,8 +42,9 @@ class CashBalance < ActiveRecord::Base
     end
   end
   @total=0
-  list=[]
+
   def get_happen_total
+    list=[]
     list.append(self.id)
 
     total =  CashBalance.where(id: list).sum("count")