What is the difference in the average number of films rented each day in Australia and Canada?
'Australia' AND 'Canada' are country; average number of films refers to AVG('Australia') AND AVG('Canada'); calculation = SUBTRACT(AVG('Australia'), AVG('Canada'))
SELECT AVG(IIF(T4.country = 'Australia', 1, 0)) - AVG(IIF(T4.country = 'Canada', 1, 0)) AS diff FROM customer AS T1 INNER JOIN address AS T2 ON T1.address_id = T2.address_id INNER JOIN city AS T3 ON T2.city_id = T3.city_id INNER JOIN country AS T4 ON T3.country_id = T4.country_id