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题解 | 统计每种性别的人数

select substring(profile,15) as gender,count(device_id) as number from user_submit group by gender

2025-03-13

0 24

题解 | 计算用户的平均次日留存率

select count(q2.device_id)/count(q1.device_id) as avg_ret from ( select distinct device_id,date from question_practice_detail) q1 left join (sele...

2025-03-12

0 29

题解 | 计算用户8月每天的练题数量

select dayofmonth(date) as day, count(question_id) as question_cnt from question_practice_detail where year(date) = 2021 and month(date)=8 group by d...

2025-03-11

0 27

题解 | 查看不同年龄段的用户明细

select device_id, gender, (case when age<20 then'20岁以下' when age between 20 and 24 then '20-24岁' when age>=25 then '25岁及以上' else '其他' end) as a...

2025-03-11

0 28

题解 | 计算25岁以上和以下的用户数量

select '25岁以下' as age_cut, count(device_id) as number from user_profile where age <25 or age is null union all select '25岁及以上' as age_cut, coun...

2025-03-11

0 35

题解 | 查找山东大学或者性别为男生的信息

select device_id, gender, age, gpa from user_profile where university ='山东大学' union all select device_id, gender, age, gpa from user_profile where...

2025-03-11

0 30

题解 | 统计每个用户的平均刷题数

select u.university,qq.difficult_level, round(count(q.question_id)/count(distinct q.device_id),4) as avg_answer_cut from user_profile u join question...

2025-03-11

0 26

题解 | 统计每个学校各难度的用户平均刷题数

select u.university, qq.difficult_level, round(count(q.question_id)/count(distinct q.device_id),4) as avg_answer_cnt from user_profile u join questi...

2025-03-11

0 33

题解 | 统计每个学校的答过题的用户的平均答题数

select u.university, round(count(q.question_id)/count(distinct q.device_id),4) as avg_answer_cnt from user_profile u join question_practice_detail q...

2025-03-11

0 29

题解 | 浙江大学用户题目回答情况

select q.device_id, q.question_id,q.result from question_practice_detail q join user_profile u on q.device_id = u.device_id where u.university ='浙江大学...

2025-03-11

0 28