SXQL> (select (:id :name :sex)
  (from (:as :person :p))
  (where (:or (:>= :age 18)
               (:is :age :null)))
  (order-by (:desc :age)))
;=> #<SXQL-STATEMENT: SELECT id, name, sex FROM person AS p WHERE ((age >= 18) OR IS(age, NULL)) ORDER BY age DESC>