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题解 | 浙江大学用户题目回答情况

SELECT t1.device_id,t2.question_id,t2.result FROM user_profile AS t1 LEFT JOIN question_practice_detail AS t2 ON t1.device_id=t2.device_id WHERE t1.u...

2025-06-26

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题解 | 分组排序练习题

SELECT university , AVG(question_cnt) AS avg_question_cnt FROM user_profile GROUP BY university ORDER BY avg_question_cnt;

2025-06-26

0 55

题解 | 分组过滤练习题

SELECT university, ROUND(AVG(question_cnt),3) AS avg_question_cnt, ROUND(AVG(answer_cnt),3) AS avg_answer_cnt FROM user_profile GROUP B...

2025-06-25

0 39

题解 | 分组计算练习题

SELECT gender,university,COUNT(*) AS user_num, ROUND(AVG(active_days_within_30),1) AS avg_active_day, ROUND(AVG(question_cnt),1) AS ...

2025-06-25

0 44

题解 | 计算男生人数以及平均GPA

SELECT COUNT(*) AS male_num ,AVG(gpa) AS avg_gpa FROM user_profile WHERE gender="male";

2025-06-25

0 50

题解 | 查找GPA最高值

SELECT ROUND(MAX(gpa),1) AS gpa FROM user_profile WHERE university="复旦大学";

2025-06-25

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题解 | 查看学校名称中含北京的用户

SELECT device_id,age,university FROM user_profile WHERE SUBSTR(university,1,2)="北京";

2025-06-25

0 44

题解 | 操作符混合运用

SELECT device_id , gender ,age ,university,gpa FROM user_profile WHERE (gpa>3.8 AND university="复旦大学") OR (gpa>3.5 AND university=&quo...

2025-06-25

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题解 | Where in 和Not in

SELECT device_id,gender,age,university,gpa FROM user_profile WHERE university IN ("北京大学","复旦大学","山东大学");

2025-06-25

0 69

题解 | 高级操作符练习(2）

SELECT device_id, gender ,age ,university ,gpa FROM user_profile WHERE university="北京大学" OR gpa>3.7;

2025-06-25

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