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 user_profile.gender; SELECT 子句中的所有非聚合列都必须出现在 GROUP BY 子句中,否则会报错
