For example, both of the following queries could benefit from indexes that
use descending ordering:
-- would benefit from an index like this:
-- CREATE INDEX c_id_desc ON Cities(city_id DESC)
SELECT * FROM Cities ORDER BY city_id DESC
-- would benefit from an index like this:
-- CREATE INDEX f_miles_desc on Flights(miles DESC)
SELECT MAX(miles) FROM Flight
-- would benefit from an index like this:
-- CREATE INDEX arrival_time_desc ON Flights(dest_airport, arrive_time DESC)
SELECT * FROM Flights WHERE dest_airport = 'LAX'
ORDER BY ARRIVAL DESC