是否可以基于Ruby on Rails活动记录中的人工操作进行排序？

Question

I want to order records based on two columns Arthimatic operation.

Ex: I has table columns on which I has to do an arthimatic operation and sort based on its value. Let the columns be math, science and total .And table name is UserMark . Typically my query looks like this

UserMark.order('(math/total) desc')

This should order the UserMarks based on math/total operation.How could it be done in Ruby on rails?

Answer 1

You have two possibilities.

You can do sorting in Active Record query itself.

UserMark.select("math/total as percentage").order('percentage desc')

or

You can do it in ruby method (this method should be in your model).

def percentage
  self.math/self.total
end

def self.sort_by_percentage
  UserMark.all.sort_by(&:percentage).reverse
end