现在运营想要了解2021年8月份所有练习过题目的总用户数和练习过题目的总次数，请取出相应结果。

selectcount(distinct device_id) as did_cnt,count(question_id) as question_cnt
fromquestion_practice_detail
wheredate like "2021-08%"

现在运营想要了解复旦大学的每个用户在8月份练习的总题目数和回答正确的题目数情况，请取出相应明细数据，对于在8月份没有练习过的用户，答题数结果返回0。

selectup.device_id,'复旦大学' as university,count(question_id) as question_cnt,sum(if (qpd.result = 'right', 1, 0)) as right_question_cnt
fromuser_profile as upleft join question_practice_detail as qpd on qpd.device_id = up.device_idand month (qpd.date) = 8
whereup.university = '复旦大学'
group byup.device_id

现在运营想要了解浙江大学的用户在不同难度题目下答题的正确率情况，请取出相应数据，并按照准确率升序输出。

selectt3.difficult_level,avg(casewhen t1.result = 'right' then 1else 0end) as correct_rate
fromquestion_practice_detail t1left join user_profile t2 on t1.device_id = t2.device_idleft join question_detail t3 on t1.question_id = t3.question_id
wheret2.university = '浙江大学'
group byt3.difficult_level
order bycorrect_rate