Question

I have some records:

Type Name
2 USA
2 USA
3 Canada
4 Mexico 
1 Canada
2 Mexico
3 USA

I just want to show the list of unique types: 1,2,3,4 (no double, triple records).
I was trying to do something like that in my view:

<% @Orders.group(:type).each do |order| %>
... showing in the table
<% end %>

But I got following error:
undefined method `group’ for #

Do I need to add some method in the controller/model?
Why – if .each method works ok in the view, group doesn’t?

Answer 1

It’s a little unclear what exactly you are trying to return/display, but I think you might want to look at #group_by (http://api.rubyonrails.org/classes/Enumerable.html#method-i-group_by).

Alternatively, look at some of the aggregate methods on this page: http://api.rubyonrails.org/classes/ActiveRecord/Calculations.html#method-i-calculate