Order by
You can order_by like this:
DQ("Book", "id").where("price > 20").order_by("name")
Descending order:
DQ("Book", "id").where("price > 20").order_by("-name")
You can have multple order by expressions.
DQ("Book", "name, publisher.name").where("price > 20").order_by("-name, publisher.name")