Sort by date AND score

Hello everybody!
I am trying to sort my search results by date, and then each day by
score.

For example:

– 26 May

  1. Score 0.74
  2. Score 0.55

– 25 May

  1. Score 0.93
  2. Score 0.68
  3. Score 0.41

I tried creating an array like this

sortable_fields = []
sortable_fields << Ferret::Search::SortField.new(:created_at_sort,
:reverse => true)
sortable_fields << Ferret::Search::SortField::SCORE

but it only works sorting by the first element (in both cases).

Any ideas?

Have a nice a day!