阿莉勒丝黛拉

题解

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题解 | #满足条件的用户的试卷完成数和题目练习数#

SELECT uid, e_tb.exam_cnt exam_cnt, IF(p_tb.question_cnt IS NOT NULL, p_tb.question_cnt,&...

Mysql

2022-03-12

1 382

题解 | #分别满足两个活动的人#

SELECT er.uid uid, 'activity1' activity FROM exam_record er INNER JOIN examin...

Mysql

2022-03-12

1 348

题解 | #每个题目和每份试卷被作答的人数和次数#

SELECT exam_id tid, COUNT(DISTINCT uid) uv, COUNT(exam_id) pv FROM exam_record GRO...

Mysql

2022-03-12

1 243

题解 | #作答试卷得分大于过80的人的用户等级分布#

不是说好的保证数量不一致吗？怎么例子里就出现数量一致的，还给我错了。只能把level也降序排序了。 SELECT ui.level level, COUNT(DISTINCT ui.uid) level_cnt FRO...

Mysql

2022-03-12

1 320

题解 | #试卷发布当天作答人数和平均分#

SELECT ei.exam_id exam_id, COUNT(DISTINCT ui.uid) uv, ROUND(AVG(er.score), 1) avg_score F...

Mysql

2022-03-12

1 302

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) tag_cut FROM exam_record INNER JOIN examination_info USING(...

Mysql

2022-03-11

1 370

题解 | #未完成试卷数大于1的有效用户#

SELECT uid, COUNT(incomplete) incomplete_cnt, COUNT(complete) complete_cnt, GROUP_CONCAT( &n...

Mysql

2022-03-11

3 407

题解 | #月总刷题数和日均刷题数#

SELECT submit_month, COUNT(question_id) month_q_cnt, ROUND(COUNT(question_id) / day, 3) a...

Mysql

2022-03-11

1 277

题解 | #平均活跃天数和月活人数#

SELECT DATE_FORMAT(submit_time, '%Y%m') month, ROUND( COUNT(DISTINCT uid, DATE_FOR...

Mysql

2022-03-11

1 362

题解 | #得分不小于平均分的最低分#

SELECT MIN(er.score) min_score_over_avg FROM exam_record er INNER JOIN examination_info e...

Mysql

2022-03-11

1 312