北岛以北

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全部文章（共38篇）

题解 | 浙江大学用户题目回答情况

select qpd.device_id, qpd.question_id, qpd.result from question_practice_detail as qpd inner join user_profile as up on up.device_id=qpd...

2025-05-23

0 22

题解 | 分组排序练习题

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

2025-05-23

0 30

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_question_...

2025-05-23

0 25

题解 | 分组计算练习题

select gender,university, count(device_id) as user_num, avg(active_days_within_30) as avg_active_day, avg(question_cnt) as avg_question_cnt from use...

2025-05-23

0 32

题解 | 计算男生人数以及平均GPA

select count(gender) as male_num,round(avg(gpa),1) as avg_gpa from user_profile where gender="male";

2025-05-19

0 30

题解 | 查找GPA最高值

select gpa from user_profile where university='复旦大学' order by gpa DESC limit 1;

2025-05-19

0 33

题解 | 查看学校名称中含北京的用户

select device_id,age,university from user_profile where university like '%北京%';

2025-05-19

0 24

题解 | 高级操作符练习(2）

select device_id,gender,age,university,gpa from user_profile where university='北京大学' or gpa > 3.7;

2025-05-18

0 22

题解 | 高级操作符练习(1)

select device_id,gender,age,university,gpa from user_profile where gender='male' and gpa >3.5;

2025-05-18

0 26

题解 | 用where过滤空值练习

select device_id,gender,age,university from user_profile where age >'';

2025-05-18

0 20