Question

I want this SQL query to be written in rails controller using find:

select id,name from questions
where id not in (select question_id from levels_questions where level_id=15)

How will I do this? I am using Rails framework and MySQL.
Thanks in advance.

Answer 1

Simple way:

ids = LevelsQuestion.all(:select => "question_id", 
        :conditions => "level_id = 15").collect(&:question_id)
Question.all(:select => "id, name", :conditions => ["id not in (?)", ids])

One shot:

Question.all(:select => "id, name",
:conditions => ["id not in (select question_id from levels_questions where level_id=15)"])