Question: Which customer has rented more movies, RUTH MARTINEZ or LINDA WILLIAMS?
SQL: SELECT T.first_name, T.last_name FROM ( SELECT T1.first_name, T1.last_name, COUNT(T1.customer_id) AS num FROM customer AS T1 INNER JOIN rental AS T2 ON T1.customer_id = T2.customer_id WHERE (T1.first_name = 'RUTH' AND T1.last_name = 'MARTINEZ') OR (T1.first_name = 'LINDA' AND T1.last_name = 'WILLIAMS') GROUP BY T1.first_name, T1.last_name ) AS T ORDER BY T.num DESC LIMIT 1