Rails way for querying join table in has_and_belongs_to_many

Posted by Michelle on Stack Overflow See other posts from Stack Overflow or by Michelle
Published on 2010-03-22T17:56:14Z Indexed on 2010/03/22 18:11 UTC
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ruby-on-rails

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activerecord

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ruby

I have a user model and a role model with a has_and_belongs_to_many reliationship. The join table is roles_users (two columns - the PK of the user and the role) and has no corresponding model.

I want to have a method that returns all users with a given role. In SQL that'd be something like

SELECT u.id FROM role.r, roles_users ru WHERE r.role_id = #{role.id} AND r.role_id = ru.role_id

I see that Rails' activerecord has a find_by_sql method, but it's only expecting one results to be returned.

What is the "Rails Way" to give me a list of users with a given role e.g.

def self.find_users_with_role(role)
  users = []
  users << # Some ActiveRecord magic or custom code here..?
end

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