pulling one field of a record into an array in a Rails 3 app

Rails 3 noob here. Currently the code in my controller below is getting the whole record in my database. I am trying to populate the array with one integer, not the whole record. The integer is contained in a table "answers" and the field name is "score". How can i modify this line in my controller to get just the one field?

@questions.each do |s|
   @ans[s.position] = Answer.where("question_id = ? AND user_id = ?", s.q_id, current_user.id )
end

UPDATE FOR CLARIFICATION: The :score can be any开发者_如何学编程 integer from 0 to 5. I would like to populate @ans[s.position] with the integer.

Thanks.

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You're very close

@questions.each do |s|
  @ans[s.position] = Answer.where("question_id = ? and user_id = ?",s.q_id,current_user.id).select(:score).first.try(:score)
end

You need to select "score" from Answer, then you need to retrieve it from the object.

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Since where could potentially return many Answers, use first to pull off the first Answer, and then score to project out the score field.

answers = Answer.where("question_id = ? AND user_id = ?", s.q_id, current_user.id )
score = answers.first.score

All together it would be:

@questions.each do |s|
   @ans[s.position] = Answer.where("question_id = ? AND user_id = ?", s.q_id, current_user.id ).first.score
end

As an optimization to only retrieve score from the database, instead of answers.*, you could use select(:score).

@questions.each do |s|
   @ans[s.position] = Answer.where("question_id = ? AND user_id = ?", s.q_id, current_user.id ).select(:score).first.score
end

See Active Record Query Interface for more about using select.

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Just include them.

@questions = Question.includes(:answers).select(:position)

Or use this

@questions = Question.select(:position)
@questions.each{ |s| @ans[s.position] = s.answers.where(:user_id => current_user.id) }