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题解 | #找出每个学校GPA最低的同学#

select device_id, university, gpa from user_profile as u where gpa = (sele...

Mysql

2022-06-26

0 317

题解 | #截取出年龄#

select substring_index(substring_index(profile, ',', -2), ',', 1) as age, &nbs...

Mysql

2022-06-26

0 322

题解 | #查看不同年龄段的用户明细#

case when 条件1 then 结果1 when 条件2 then 结果2 when 条件3 then 结果3 else 结果4 end 这就相当于if ...

Mysql

2022-06-26

0 253

题解 | #计算25岁以上和以下的用户数量#

case when 条件1 then 结果1 else 结果2 end 相当于 if(条件1）结果1 &nbs...

Mysql

2022-06-26

0 301

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_d...

Mysql

2022-06-26

0 308

题解 | #每份试卷每月作答数和截止当月的作答总数。#

select distinct exam_id, date_format(start_time, '%Y%m') as start_month, &nbs...

Mysql

2022-02-13

0 278

题解 | #统计有未完成状态的试卷的未完成数和未完成率#

select exam_id, sum(if(submit_time is null, 1, 0)) as incomplete_cn...

Mysql

2022-02-13

0 371

题解 | #0级用户高难度试卷的平均用时和平均得分#

select ui.uid, round(avg(if(submit_time is null, 0, score)), 0) as a...

Mysql

2022-02-13

0 349

题解 | #试卷发布当天作答人数和平均分#

select exam_id, count(distinct uid) as uv, round(avg(score), 1) as&...

Mysql

2022-02-13

0 335

题解 | #作答试卷得分大于过80的人的用户等级分布#

select level, count(distinct ui.uid) as level_cnt from examination_info as ei join exam_record ...

Mysql

2022-02-13

0 431