Finding records where one attribute is greater than another

Question

I want to find any product that has a higher ip_solid than ip_liquid.

I am trying to do the following:

Product.where("ip_solid > ?", :ip_liquid).count

However, it seems that :ip_liquid is not being read out from each object, and is probably evaluating to 0 or nil. Is something like this even possible?

Answer 1

Product.where("ip_solid > ip_liquid").count should do it as long as ip_liquid is a field in the database and not a method on your model