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