What are the top 2 platforms with the most sales in North America?
platforms refers to platform_name; most sales refers to MAX(num_sales); North America refers to region_name = 'North America';
SELECT T4.platform_name FROM region AS T1 INNER JOIN region_sales AS T2 ON T1.id = T2.region_id INNER JOIN game_platform AS T3 ON T2.game_platform_id = T3.id INNER JOIN platform AS T4 ON T3.platform_id = T4.id WHERE T1.region_name = 'North America' ORDER BY T2.num_sales DESC LIMIT 2