rails query not in statement formatting correct

Question

I do this:

    check1 = inquiries.select("question_id").where(:membership_id => self.id)

This returny a active Record array with entries like this:

#<ActiveRecord::AssociationRelation [#<Inquiry id: nil, question_id: 21113>,

Now I want to select in a secon query all questions which are not in the inqueries

Tried this:

lesson.questions.where("NOT IN ?",check1)

But that does not work, probably because the first query returns an active record array with 2 values for each object?

how could look like a solution?

Answer 1

Make use of pluck

check1 = inquiries.where(membership_id: self.id).pluck(:question_id)
#=> [1, 2, 3] # List of ids 

lesson.questions.where("id NOT IN (?)", check1)

# OR 

lesson.questions.where.not(id: check1)

NOTE: If you have an association between lesson and inquiries you can make use of joins and get the result in one query itself.