https://www.nowcoder.com/practice/7d9a7b2d6b4241dbb5e5066d7549ca01?tpId=199&tqId=1975665&ru=%2Fta%2Fsql-quick-study&qru=%2Fta%2Fsql-quick-study%2Fquestion-ranking
select count(gender) male_num, round(AVG(gpa),1) avg_gpa from user_profile WHERE gender = 'male' GROUP BY gender