the :group and :having options on a has_many

I noticed the has_many relationship method allows for :group and :having options. Can anyone provide an example of when these would be used in a has_many?

Something like this? has_many :accounts, :select => 'name, SUM(cash) as money', :group => :name, :having => '"created_at > ?", 2.days.ago'

I cant ever imagine a has_many like that above. But is that why they include the :group and :having options, for sake of completeness?

thanks for response