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题解 | #浙大不同难度题目的正确率#

SELECT difficult_level,SUM(IF(result='right',1,0))/COUNT(*) AS correct_rateFROM user_profile AS upINNER JOIN question_practice_detail AS qpdINNER JOIN...

2021-08-31

24 1170

题解 | #21年8月份练题总数#

SELECT COUNT(DISTINCT device_id) AS did_cnt,COUNT(device_id) AS question_cntFROM question_practice_detailWHERE YEAR(date)=2021 AND MONTH(date)=8

2021-08-31

14 1276

题解 | #统计复旦用户8月练题情况#

需要判断月份通过IF语句可以设置值用SUM统计所有值 SELECT up.device_id,up.university,SUM(IF(MONTH(date)=8,1,0)) AS question_cnt,SUM(IF(MONTH(date)=8 AND result='right',1,0)...

2021-08-31

101 4446

题解 | #查找山东大学男生的GPA#

# if判断 SELECT IF(age<25 OR age IS NULL,'25岁以下','25岁以及上') age_cut,COUNT(device_id) Number FROM user_profile GROUP BY age_cut # 联合查询 SEL...

2021-08-31

224 7891

题解 | #查找山东大学男生的GPA#

SELECT device_id,gender,age,gpaFROM user_profileWHERE university = '山东大学'UNION ALLSELECT device_id,gender,age,gpaFROM user_profileWHERE gender = 'male...

2021-08-31

2 708