CREATE TABLE routes (rid DECIMAL, dst_apid DECIMAL, dst_ap TEXT, src_apid DECIMAL, src_ap TEXT, alid DECIMAL, airline TEXT, codeshare TEXT)
CREATE TABLE airlines (alid DECIMAL, name TEXT, iata TEXT, icao TEXT, callsign TEXT, country TEXT, active TEXT)
CREATE TABLE airports (apid DECIMAL, name TEXT, city TEXT, country TEXT, x DECIMAL, y DECIMAL, elevation DECIMAL, iata TEXT, icao TEXT)

How many airports are there per country? Order the countries by decreasing number of airports.
SELECT COUNT(*), country FROM airports GROUP BY country ORDER BY COUNT(*) DESC
SELECT COUNT(*), "country" FROM "airports" GROUP BY "country" ORDER BY COUNT(*) DESC NULLS LAST