Michael Pavling wrote: > On 21 April 2010 12:10, DanC <[email protected]> wrote: >> @topics = Topic.find(:all, :conditions => ["forum_id = ?", >> @forum.id], :order => "total_replies DESC") >> >> but I get the error Mcolumn "total_replies" does not exist >> >> I know the column doesn't exist, but the question is, how can I get >> the 'total_replies' to behave as a column. > > You can't - it's a method on a model, and the DB knows nothing about it. > But you can add a column that keeps the value of associated replies > and then the query will work. Rails will do this for you with a > "counter_cache". > > http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html > (I'm still getting the hijacked domain, so I hope that's the right link)
You could also select it as an additional column (by getting it from the SQL count() function), although I don't know how well ActiveRecord would deal with that. Best, -- Marnen Laibow-Koser http://www.marnen.org [email protected] -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
