Facet count for an arbitrary dimension on the results of a search, uses #where_values

gistfile1.rb

    def facet_count(facet)
      # Work out some useful strings.
      facet_table = facet.table_name
      facet_sym = facet_table.to_sym
      facet_id_name = facet.name.foreign_key

      # Build the base query in terms of the
      # model being used to facet the results.
      #
      # We join to Company as that is used to filter
      # out inactive companies.
      facet_counts = facet.
        joins(:antibodies => :company).
        group("#{facet_table}.id").
        select(
          "#{facet_table}.id id, #{facet_table}.name, #{facet_id_name}, count(*) count"
        ).order('count DESC')

      # Take the Antibodies scope, resulting from the
      # search, and apply its clauses to 
      scoped.where_values.each do |condition|
        facet_counts = facet_counts.where(condition)
      end
      
      # Convert into a thing/count pair
      facets.collect {|a| [a, a.count]}
    end

The 'facet' parameter should be a model.