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题解 | #计算用户8月每天的练题数量#
SELECT day(date) day, count(question_id) question_cnt FROM question_practice_detail WHERE YEAR(date) = 2021 and MONTH(date) = 8 GROUP BY date;
Mysql
2021-11-17
0
192
题解 | #查看不同年龄段的用户明细#
SELECT device_id, gender, case when age < 20 then "20岁以下" when age < 24 then "20-24岁" when age >= 25 then "25岁及以上" wh...
Mysql
2021-11-17
0
179
题解 | #计算25岁以上和以下的用户数量#
SELECT CASE when age<25 or age IS null then "25岁以下" when age>=25 then "25岁及以上" end age_cut, count(*) number FROM user_profil...
Mysql
2021-11-17
0
160
题解 | #查找山东大学男生的GPA#
SELECT device_id, gender, age, gpa FROM user_profile WHERE university = "山东大学" UNION ALL SELECT device_id, gender, age, ...
Mysql
2021-11-17
0
155
题解 | #统计每个学校各难度的用户平均刷题数#
SELECT up.university, difficult_level, COUNT(qpd.result) / COUNT(distinct qpd.device_id) avg_answer_cnt FROM user_profile up JOIN question...
Mysql
2021-11-17
0
287
题解 | #统计每个学校各难度的用户平均刷题数#
SELECT up.university, qd.difficult_level, COUNT(qpd.question_id) / COUNT(DISTINCT qpd.device_id) avg_answer_cnt FROM user_profile up JOIN ...
Mysql
2021-11-17
0
162
题解 | #统计每个学校的答过题的用户的平均答题数#
SELECT u.university, round(count(q.result)/count(DISTINCT q.device_id),4) avg_answer_cnt FROM user_profile u JOIN question_practice_detail q ON u.devi...
Mysql
2021-11-17
0
197
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