如何使用Ruby on Rails上的Join将两个或多个参数传递给两个不同的表

Question

i have the exams table, the subjects table, and the exam_subjects table. i want to filter lets say by Exam.id and Subject.id on the WHERE how do i pass those parameters.

@exams = Exam.joins(exam_subjects: :subject).where(:exam_id => params[:exam_id], :subject_id => params[:subject_id])

Answer 1

Have you tried something like

@exams = Exam.joins(exam_subjects: :subject).where(:id => [params[:exam_id], params[:subject_id]])

?

Answer 2

You can use an string as a parameter in the where condition:

@exams = Exam.joins(exam_subjects: :subject).where('id = ? AND exam_id = ?', params[:exam_id], params[:subject_id])

Take a look at Pure String Conditions on active record.