arel_columns

# File activerecord/lib/active_record/relation/query_methods.rb, line 1065
    def arel_columns(columns)
      columns.map do |field|
        if (Symbol === field || String === field) && columns_hash.key?(field.to_s) && !from_value
          arel_table[field]
        elsif Symbol === field
          connection.quote_table_name(field.to_s)
        else
          field
        end
      end
    end