题解 | #分组过滤练习题#

select university,avg_question_cnt,avg_answer_cnt from (select university,avg(question_cnt) as avg_question_cnt,avg(answer_cnt) as avg_answer_cnt from user_profile group by university) as subqurey where avg_question_cnt<5 or avg_answer_cnt <20;这是第一种查询方式，第二种查询时having查询，select university，avg(question_cnt) as avg_question_cnt,avg(answer_cnt) as avg_answer_cnt from user_profile group by university having avg_question_cnt<5 or avg_answer_cnt <20;