牛客金坷垃

分类

/ 注册

全部文章（共21篇）

题解 | #找出每个学校GPA最低的同学#

SELECT device_id, university, gpa FROM ( SELECT *, dense_rank() over( partition by university order by gpa) AS rankn FROM user_profile ) AS a WHERE a...

2024-05-29

0 139

题解 | #统计每种性别的人数#

SELECT substring_index (profile, ',', -1) as gender, count(*) as number FROM user_submit GROUP BY gender; 用的substring_index写是写出来了，但居然...

2024-05-29

0 133

题解 | #计算用户8月每天的练题数量#

SELECT day(date) AS day, COUNT(question_id) AS question_cnt FROM question_practice_detail WHERE year(date)=2021 AND month(date) = 8 GROUP BY date; 猛猛...

2024-05-29

0 133

题解 | #查看不同年龄段的用户明细#

SELECT device_id, gender, CASE WHEN age<20 THEN "20岁及以下" WHEN age BETWEEN 20 and 24 THEN "20-24岁"...

2024-05-09

0 161

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_profil...

2024-05-09

0 115

题解 | 手把手教程#统计每个用户的平均刷题数#

SELECT up.university, qd.difficult_level, ROUND(COUNT(qpd.question_id)/COUNT(distinct qpd.device_id), 4) AS avg_answer_cnt FROM question_practice_deta...

2024-05-08

0 140

题解 | 分步写#统计每个学校各难度的用户平均刷题数#

SELECT up.university,qd.difficult_level, (COUNT(qpd.question_id) / COUNT(distinCt qpd.device_id)) AS avg_answer_cnt From question_practice_detail as q...

2024-05-08

0 216

#统计每个学校各难度的用户平均刷题数#

写不出来，以后凡是思考超过5min的题，立刻看题解参考第二高赞题解 SELECT u.university, qd.difficult_level, COUNT(q.quetion_id) / COUNT(DISTINCT(q.device_id)) AS avg_answer_cnt FR...

2024-04-28

0 159

题解 | #统计每个学校的答过题的用户的平均答题数#

分析完精华题解的思路后，自己写了一遍 SELECT university, COUNT(question_id) / COUNT(distinct qpd.device_id) AS avg_answer_cnt FROM question_practice_detail AS qpd INNER ...

2024-04-28

0 144

题解 | #统计每个学校的答过题的用户的平均答题数#

SELECT up.university, AVG(num_question) AS avg_answer_cnt FROM user_profile AS up JOIN( SELECT device_id, COUNT(question_id) AS num_question ...

2024-04-28

0 116