Hi, in my project I needed to manage a set of query that fondamentally was a great sql union. I had a cycle that was running a query, and the resultant recordset was added to a variable with the += method. After some attempts I setted this var as Array because I found that the sum of ActiveRecord::Relation gave me an Array of objects!
But this was only half the job: I needed to work on that Array with aggregation function as sum and found nothing to help me than write my own code. So the idea! The sum of ActiveRecord::Relation objects returns a special Union object? This object act as a memory table and expose methods like select, ,find, group, sum, average and all the other valid for AR::Model object, the difference is that the fields of this "table" will be created at runtime, based on the first AR::Relation object passed to and all the other AR::Relation added need to have the same structure. In this manner i wiil be easy to do @recs = Union.new Model1.each do |m1| @recs += Model2.select...where....(:att1=>m1.attr) #what will be necessary end @recs.select('f1 as myfield, sum(f2) as total, average(f3) as avv').group(:id_field) I propose this class because I am not able to achieve. Thanks for read Giorgio -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/ce4a7cf7-5358-4a68-8866-510a08b6a2f6%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.