人生苦短，但求成长

题解

/ 注册

全部文章 / 题解（共86篇）

题解 | #统计每个学校的答过题的用户的平均答题数#

select t1.university,round(count(1)/count(distinct t1.device_id), 4) as avg_answer_cnt from user_profile t1 join question_practice_detail t2 on t1.dev...

Mysql

2022-03-11

1 292

题解 | #浙江大学用户题目回答情况#

select t1.device_id,t1.question_id,t1.result from question_practice_detail t1 join user_profile t2 on t1.device_id = t2.device_id where t2.university ...

Mysql

2022-03-11

5 265

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

Mysql

2022-03-11

1 254

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 ...

Mysql

2022-03-11

4 335

题解 | #分组计算练习题#

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

Mysql

2022-03-11

4 396

题解 | #操作符混合运用#

select device_id,gender,age,university,gpa from user_profile where (gpa > 3.5 and university = '山东大学') or (gpa > 3.8 and university = '复旦大学')

Mysql

2022-03-11

7 343