Rails: Getting random product within several categories -

I have a question about random entries in Rail 3. I have two models:

  class product & lt; ActiveRecord :: Base is_to: Category self.random Product.find: first,: offset = & gt; (ProductCount * ActiveSupport :: SecureRandom.random_number) .to_i End and Class Category & lt; ActiveRecord :: Base has_many: products end   
 I am able to obtain a random product within all products using a random offset cast for Int. But I also want to be able to get random products within the given categories. I tried to do something like this, but due to the offset index it does not work:  
  class product & lt; ActiveRecord :: Base is_to: Category includes self.random cat = {"Mac", "windows"] (categories). Where (: categories = & gt; {: name = & gt; cat}). Where (: First ,: offset => (ProductCount * ActiveSupport :: SecureRandom.random_number) .to_i) End End   
 Anyone who knows better solution here?  
 thx! Tux   
 
 
 You can try it a bit more:  
  class Product & lt; ActiveRecord :: Base DF self.random (cat = zero) cat || =% W [MAC Windows] includes (: Categories). SAME (: Categories = & gt; {: name = & gt; CAT}) Offset (Active:: SecureRendam.Rand_Number (Self Coat). First End & / Code>  
 Many convenient accessory methods such as  offset  and  first  in Rail 3 that give you the  where  section The number of arguments can be reduced.  
 If there is a problem connecting with you, where there is a number of similar products Compared to the number of total products, you need to use the  ORDER BY RAND ()  In most cases this is not really a great deal performance and you can always be sure that this is your Works for.