题解 | #分组过滤练习题#

select university , sum(question_cnt)/count(question_cnt) AS avg_question_cnt, sum(answer_cnt)/count(answer_cnt) AS avg_answer_cnt from user_profile
group by university 
having avg_question_cnt<5 or avg_answer_cnt<20;

having的简单应用，对分组后数据进行二次过滤