select
    university,
    round(avg(question_cnt), 3) as avg_question_cnt,
    round(avg(answer_cnt), 3) as avg_answer_cnt
from
    user_profile
    group by
    1
having
    avg_question_cnt < 5
    or avg_answer_cnt < 20

where 聚合前筛选

having 聚合后筛选