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题解 | #查看不同年龄段的用户明细#

select device_id, gender, (case when age >= 20 && age <= 24 then '20-24岁' when age >= 25 then '25岁及以上' ...

2023-03-29

0 149

题解 | #计算25岁以上和以下的用户数量#

select age_cut, count(age_cut) as "number" from (select (case when age >= 25 then '25岁及以上' when age < 25 || age is null then '25岁以下' end) as "ag...

2023-03-29

0 164

题解 | #统计每个用户的平均刷题数#

select u.university, d.difficult_level, count(q.question_id) / count(distinct q.device_id) as "avg_answer_cnt" from user_profile u left join ...

2023-03-29

0 158

题解 | #统计每个学校各难度的用户平均刷题数#

select p.university, d.difficult_level, count(q.question_id) / count(distinct q.device_id) as "avg_answer_cnt" from user_profile p left join ...

2023-03-29

0 197

题解 | #统计每个学校的答过题的用户的平均答题数#

select u.university, count(question_id) / count(distinct q.device_id) as "avg_answer_cnt" from user_profile u left join question_practice_det...

2023-03-29

0 215

题解 | #浙江大学用户题目回答情况#

select q.device_id, q.question_id, q.result from user_profile u left join question_practice_detail q on u.device_id = q.device_id where u.uni...

2023-03-29

0 151

题解 | #浙江大学用户题目回答情况#

select device_id, question_id, result from question_practice_detail where device_id = (select device_id from user_profile ...

2023-03-29

0 123

题解 | #分组排序练习题#

select university, avg(question_cnt) as "avg_question_cnt" from user_profile group by university having avg_question_cnt >= 1 order by avg_question...

2023-03-29

0 144

题解 | #分组过滤练习题#

select university, avg(question_cnt) as "avg_question_cnt", avg(answer_cnt) as "avg_answer_cnt" from user_profile group by university having avg_quest...

2023-03-29

0 147

题解 | #分组计算练习题#

select gender, university, count(*) as "user_num", avg(active_days_within_30) as "avg_active_day", avg(q...

2023-03-29

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