脑袋发芽
脑袋发芽
全部文章
分类
归档
标签
去牛客网
登录
/
注册
脑袋发芽的博客
全部文章
(共4篇)
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
215
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
280
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
266
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
333