Find by has_many models size

Question

I'm developing Rails 2.3.8 Ruby 1.8.7 and PostgreSQL.

When I want to search model which has less than specific size, how to write find conditions?

For example, I want to search Topic which has less than 5 comments.

class Topic < ActiveRecord::Base
     has_many :comments
end

class Comment < ActiveRecord::Base
     belongs_to :topic
end

Topic.find(:all,:include => :comments, :conditions => [(which has less than 5 comments)])

Will this help? http://lukaszwrobel.pl/blog/sql-having-clause-in-rails-activerecord You have to use "select as" and "having" together. — Sujith Surendranathan, Aug 22 '12 at 02:02

score 0 · Answer 1 · answered Aug 22 '12 at 02:11

Will this solve your problem?

Topic.find(:all, :select => 'topics.*, count(comments.id) AS comment_count', :joins => 'INNER JOIN comments ON comments.topic_id = topics.id', :group => 'comments.topic_id HAVING count(comments.topic_id) < 5' )

Find by has_many models size

1 Answers1