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题解 | row_number+表连结

select e.first_name from employees e join(select first_name, row_number() over(order ...

Mysql

2022-09-10

0 176

题解 | 统计salary的累计和

select emp_no,salary,sum(salary) over(order by emp_no) as running_total from salaries where to_date='9999-01-01';

Mysql

2022-09-10

0 212

题解 | #删除+查询

delete from titles_test where id not in(select * from (select min(id) fro...

Mysql

2022-09-10

0 202

题解 | #group_concat(separator)#

/*select uid,sum(if(submit_time is null,1,0)) incomplete_cnt, sum(if(submit_time is not null,1,0)) complete_cn...

Mysql

2022-09-07

0 254

题解 | #126.平均活跃天数和月活人数#

select distinct concat(year(submit_time),lpad(month(submit_time),2,'0')) month, round(count(distinct uid,date_format(submit_time,&...

Mysql

2022-09-06

0 248

题解 | #得分不小于平均分的最低分#

描述请从试卷作答记录表中找到SQL试卷得分不小于该类试卷平均得分的用户最低得分。 select min(score) min_score_over_avg from exam_record ...

Mysql

2022-09-06

0 340

题解 | #统计作答次数#

select count(id) total_pv,sum(if(score is not null,1,0)) complete_pv, count(distinct if(submit_time is no...

Mysql

2022-09-06

0 175

题解 | outer join

(select prod_name,order_num from Products p left join OrderItems o on p.prod_id=o.prod_id) union (s...

Mysql

2022-09-04

0 228

题解 | #统计复旦用户8月练题情况#

题目：现在运营想要了解复旦大学的每个用户在8月份练习的总题目数和回答正确的题目数情况，请取出相应明细数据，对于在8月份没有练习过的用户，答题数结果返回0. select u.device_id,university,count(question_id) que...

Mysql

2022-09-03

0 197

题解 | #找出每个学校GPA最低的同学#

题目：现在运营想要找到每个学校gpa最低的同学来做调研，请你取出每个学校的最低gpa。 select device_id,u2.university,u2.gpa from (select university, min(gpa) as&n...

Mysql

2022-09-03

0 271