题解 | 分组计算练习题

SELECT
  gender,
  university,
  COUNT(*) AS user_num,
  ROUND(AVG(active_days_within_30), 1) AS avg_active_day,
  ROUND(AVG(question_cnt), 1) AS avg_question_cnt
FROM user_profile
GROUP BY gender, university
ORDER BY gender ASC, university ASC;

ORDER BY：表示要对查询结果排序。

gender ASC：按性别从小到大排序。比如，female 会排在 male 前面（因为按字母顺序）。

university ASC：如果两个记录的性别相同，就进一步按学校名字的字母顺序从小到大排序。