arel_column_aliases_from_hash

# File activerecord/lib/active_record/relation/query_methods.rb, line 2234
      def arel_column_aliases_from_hash(fields)
        fields.flat_map do |key, columns_aliases|
          table_name = key.is_a?(Symbol) ? key.name : key
          case columns_aliases
          when Hash
            columns_aliases.map do |column, column_alias|
              arel_column_with_table(table_name, column)
                .as(model.adapter_class.quote_column_name(column_alias.to_s))
            end
          when Array
            columns_aliases.map do |column|
              arel_column_with_table(table_name, column)
            end
          when String, Symbol
            arel_column(key)
              .as(model.adapter_class.quote_column_name(columns_aliases.to_s))
          end
        end
      end