勤奋努力的追梦人想要offer

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题解 | 浙大不同难度题目的正确率

select qd.difficult_level, round(sum(case when qpd.result='right' then 1 else 0 end)/count(qpd.question_id),4) as correct_rate from user_p...

2025-06-16

0 25

题解 | 统计复旦用户8月练题情况

select u.device_id, u.university, count(qpd.question_id) as question_cnt, sum(case when qpd.result='right' then 1 else 0 end) as right...

2025-06-16

0 19

题解 | 找出每个学校GPA最低的同学

SELECT u.device_id, u.university, u.gpa FROM user_profile u JOIN ( SELECT university, MIN(gpa) AS min_gpa F...

2025-06-16

0 14

题解 | 截取出年龄

select substring_index(substring_index(profile,',',3),',',-1) as age, count(device_id) as number from user_submit group by substring_i...

2025-06-16

0 12

题解 | 提取博客URL中的用户名

select device_id, substring_index(blog_url,'url/',-1) as user_name from user_submit; select device_id, substring_index(blog_url,'url/',-1)...

2025-06-16

0 13

题解 | 统计每种性别的人数

select substring_index(substring_index(profile,',',-1),',',1) as gender, count(device_id) as number from user_submit group by substri...

2025-06-16

0 17

题解 | 计算用户的平均次日留存率

select count(date2)/count(date1) as avg_ret from( select distinct qpd.device_id, qpd.date as date1, uniq_id_date.date...

2025-06-16

0 19

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 date like '2021-08-%' group by day(date); 从名为quest...

2025-06-16

0 13

题解 | 查看不同年龄段的用户明细

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

2025-05-13

0 35

题解 | 计算25岁以上和以下的用户数量

select case when age < 25 or age is null then '25岁以下' else '25岁及以上' end as age_cut, count(*) as number from user_p...

2025-05-13

0 28