ActiveRecord find all parents that have associated children

Question

I don\'t know why I can\'t figure this out, I think it should be fairly simple. I have two models (see below). I\'m trying to come up with a named scope for SupplierCatego

Answer 1

I believe it would be something like

#model SupplierCategory
named_scope :with_suppliers, 
   :joins => :suppliers,
   :select => "distinct(supplier_categories), supplier_categories.*",
   :conditions => "suppliers.supplier_categories_id = supplier_categories.id"

Let me know if it works for you.

Edit: Using fl00r's idea:

named_scope :with_suppliers, 
   :joins => :suppliers,
   :select => "distinct(supplier_categories), supplier_categories.*",
   :having => "count(supliers.id) > 0"

I believe this is the faster way.