instance method arel_column

# File activerecord/lib/active_record/relation/query_methods.rb, line 1991
      def arel_column(field)
        field = field.name if is_symbol = field.is_a?(Symbol)

        field = model.attribute_aliases[field] || field.to_s
        from = from_clause.name || from_clause.value

        if model.columns_hash.key?(field) && (!from || table_name_matches?(from))
          table[field]
        elsif /\A(?<table>(?:\w+\.)?\w+)\.(?<column>\w+)\z/ =~ field
          arel_column_with_table(table, column)
        elsif block_given?
          yield field
        elsif Arel.arel_node?(field)
          field
        else
          Arel.sql(is_symbol ? model.adapter_class.quote_table_name(field) : field)
        end
      end