List the full names of all countries that contain at least 2 cities of at least 5,000,000 people. Do this as a single query. (JOIN) Expected results:
+----------+ | name | +----------+ | Brazil | | India | | China | | Pakistan | +----------+ 4 rows in set (0.03 sec)
SELECT DISTINCT c.name FROM countries c JOIN cities ci1 ON ci1.country_code = c.code JOIN cities ci2 ON ci2.country_code = c.code WHERE ci1.id < ci2.id AND ci1.population >= 5000000 AND ci2.population >= 5000000;