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题解 | 分组计算练习题

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

2025-03-11

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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') order...

2025-03-11

0 31

题解 | 查找当前薪水详情以及部门编号dept_no

select s.emp_no,s.salary,s.from_date,s.to_date,d.dept_no from dept_manager d left join salaries s on d.emp_no = s.emp_no order by s.emp_no 只要领导的信息，...

2025-03-10

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题解 | 找出每个学校GPA最低的同学

select a.device_id,a.university,a.gpa from (select device_id,university,gpa,dense_rank() over (partition by university order by gpa) as ranking from u...

2025-03-10

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题解 | 查询连续登陆的用户

select b.user_id from (select a.user_id,count(a.primary_date) as continue_num from (select l.user_id,date_sub(date(l.log_time),interval row_number() ...

2025-03-09

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题解 | 分析客户逾期情况

select customer_tb.pay_ability, concat(round((count(distinct case when loan_tb.overdue_days is not null then loan_tb.customer_id end)/count(distinct ...

2025-03-09

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题解 | 每个月Top3的周杰伦歌曲

select * from( select month(play_log.fdate) as month,row_number() over (partition by month(play_log.fdate) order by count(play_log.song_id) desc,play_...

2025-03-09

0 30

题解 | 21年8月份练题总数

select count(distinct device_id) as did_cnt,count(question_id) as question_cnt from question_practice_detail where year(date) = 2021 and month (date)...

2025-03-09

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