CODEWITHSUNDEEP
ruby-on-railsactiverecordruby-on-rails-4
xaph
xaph

Reputation: 663

Rails 4 Active Records: Order by position on association

I have two models:

class Country
  has_many :competitions
end

class Competition
  belongs_to :country
end

Competition class has a position attribute. Admin can sort competitions by position. I want to sort countries with the minimum position of its competitions. I also want to joing competitions with country. How can i achieve that?

I want an output like:

X Country: (is at first order because Xcomp1's position is 1)
  Xcomp1 (position: 1)
  Xcomp2 (position: 12)

A Country: 
  Acomp1 (position:2)
  Acomp2 (position:3)

Z Country: (is at last position because minimum position of its competitions are higher than other ones)
  Zcomp1 (position:5)

Upvotes: 0

Views: 1037

Answers (1)

David Aldridge
David Aldridge

Reputation: 52356

I think you'd have to:

Country.order("(select min(position) from competitions where competitions.country_id = countries.id) asc")

I'm not sure how that syntax holds up across different RDBMSs -- should be good on PostgreSQL and Oracle

Upvotes: 1

Related Questions