这道题很酷
基础的考察了日期函数的应用
year(), month(), day() 这几个日期函数用法,以及如何比价日期

上代码:
select 
    day(date) day,
    count(question_id) 
from   
    question_practice_detail
where
    month(date) = 8
    and
    year(date) = 2021
group by
    date;