彼时d纸鸢

分类

题解(22)

/ 注册

全部文章（共21篇）

题解 | #分别满足两个活动的人#

SELECT uid, "activity1" activity FROM exam_record e1 GROUP BY &nbs...

Mysql

2021-11-07

0 352

题解 | #每个题目和每份试卷被作答的人数和次数#

order by不能直接出现在union的子句中，但是可以出现在子句的子句中。 SELECT * FROM ( &n...

Mysql

2021-11-07

0 364

题解 | #作答试卷得分大于过80的人的用户等级分布#

SELECT ui. LEVEL, count(*) level_cnt FROM examination_info ei JOIN exam_record...

Mysql

2021-11-07

0 289

题解 | #试卷发布当天作答人数和平均分#

SELECT ei.exam_id, count(DISTINCT uid) uv, round(avg(score), 1) avg_score FROM...

Mysql

2021-11-07

0 378

题解 | #月均完成试卷数不小于3的用户爱作答的类别#

SELECT tag, count(*) tag_cnt FROM exam_record r JOIN examination_info i USING ...

Mysql

2021-11-07

0 398

题解 | #未完成试卷数大于1的有效用户#

SELECT uid, sum( IF ( &...

Mysql

2021-11-07

0 421

题解 | #平均活跃天数和月活人数#

SELECT date_format(submit_time, '%Y%m') submit_month, count(*) month_q_cnt, ro...

Mysql

2021-11-07

0 335

题解 | #平均活跃天数和月活人数#

SELECT DATE_FORMAT(start_time, '%Y%m') mon, round( cou...

Mysql

2021-11-07

0 378

题解 | #得分不小于平均分的最低分#

select min(score) FROM exam_record a JOIN examination_info b ON a.exam_id = b.exam_id ...

Mysql

2021-10-21

0 438

题解 | #统计作答次数#

SELECT count(*) total_pv, count(score) complete_pv, ( SELECT count(DISTINCT exam_id) FROM exam_record WHERE score&nbs...

Mysql

2021-10-21

0 376