GB279824

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全部文章（共162篇）

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, count(d...

2025-05-17

0 19

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 ge...

2025-05-17

0 20

题解 | 统计每个用户的平均刷题数

# select university, difficult_level, # round(count(answer_cnt)/count(distinct u.device_id),4) as avg_answer_cnt # from user_profile u, question_pract...

2025-05-17

0 19

题解 | 统计每个学校各难度的用户平均刷题数

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

2025-05-17

0 21

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 as u, question_practice_deta...

2025-05-17

0 19

题解 | 浙江大学用户题目回答情况

# 方法一 # select device_id, question_id, result # from question_practice_detail # where device_id in ( # select device_id # from user_profile # ...

2025-05-17

0 19

题解 | 分组排序练习题

select university, round(avg(question_cnt), 4) as avg_question_cnt from user_profile group by university order by avg_question_cnt ASC;

2025-05-16

0 18

题解 | 分组过滤练习题

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 university ...

2025-05-16

0 19

题解 | 分组计算练习题

select gender, university, count(*) as user_num, round(avg(active_days_within_30), 1) as avg_active_day, round(avg(question_cnt), 1) as avg_question_c...

2025-05-16

0 19

题解 | 计算男生人数以及平均GPA

select count(gender) as male_num, avg(gpa) as avg_gpa from user_profile where gender = 'male';

2025-05-16

0 22