CREATE TABLE players (country_code VARCHAR(255), first_name VARCHAR(255), player_id VARCHAR(255)); CREATE TABLE rankings (player_id VARCHAR(255), tours VARCHAR(255))
Find the first name and country code of the player who did the most number of tours.
    
SQL: SELECT T1.country_code, T1.first_name FROM players AS T1 JOIN rankings AS T2 ON T1.player_id = T2.player_id ORDER BY T2.tours DESC LIMIT 1