So Oracle has NULLS FIRST, which I can use to have null values sorted at the top followed by my column value in descending order:
ORDER BY date_sent NULLS FIRST
What is comparable in SQL Server? There are these alternatives, assuming the date values are NULL or in the past:
ORDER BY ISNULL(date_sent, GETDATE()) DESC
ORDER BY (CASE WHEN t.setinactive IS NULL THEN 1 ELSE 2 END), t.setinactive DESC
ORDER BY -CAST(date_sent as int) ASC
Any others?