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题解 | #浙大不同难度题目的正确率#

SELECT qd.difficult_level, IFNULL (SUM(qp.result = 'right') / COUNT(*), 0) AS accuracy_rate FROM user_profile up JOIN question_practic...

2023-08-16

0 219

题解 | #截取出年龄#

select substring_index (substring_index (profile, ',', -2), ',', 1) age, count(device_id) as number from user_submit group by age;

2023-08-16

0 286

题解 | #统计每个学校的答过题的用户的平均答题数#

select up.university,count(qpd.question_id) / count( distinct qpd.device_id) avg_answer_cnt from user_profile up join question_practice_detail qpd whe...

2023-08-15

0 267

题解 | #查找除复旦大学的用户信息#

select device_id,gender,age,university from user_profile where age is not null; --为什么这样写也能通过

2023-08-15

0 339