Rails: How to use instance method in Active Record Query

I am having a filter query which should return all the records where either

1. attribute (column) “status” is not “done”, or
2. instance method “completeness_status” does not return “done”

The query is something like that: Studies.where("studies.status != ? OR studies.completeness_status != ?", "done", "done") but I am getting error that column completeness_status does not exist.

Unfortunately, the column status is not continuously updated, so I cannot use it only. Also, the instance method “completeness_status” is based on records from other tables. I try to add a scope to my model and use this instance method as scope but also I was not successful. Also, I tried to used it as class method but then I do not know how to call it from where clause.

def self.completeness_status(study)
 # code
end

or

def self.completeness_status_done?(study)
 # code return true or false
end

Any Idea how to solve that. Thanks.

Answer

You cannot use instance methods inside your query. But if you like to check the condition of completeness for only one row, then you can use it as instance method:

first_study = Study.first
first_study.completeness_status_done?

Also, if you provide more information about what is going on inside your completeness_status_done? then maybe I can give you some ideas to use scopes.

https://guides.rubyonrails.org/active_record_querying.html