Question: What is the percentage of female OPPO users against the male OPPO users?
SQL: SELECT SUM(IIF(T2.gender = 'F', 1, 0)) * 100 / COUNT(T2.device_id) AS perFemale , SUM(IIF(T2.gender = 'M', 1, 0)) * 100 / COUNT(T2.device_id) AS perMale FROM phone_brand_device_model2 AS T1 INNER JOIN gender_age AS T2 ON T2.device_id = T1.device_id WHERE T1.phone_brand = 'OPPO'