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50道SQL经典练习题

news 来源：原创 2025/4/22 11:22:22

学生表 Student

create table Student(SId varchar(10),Sname varchar(10),Sage datetime,Ssex varchar(10));insert into Student values('01' , '赵雷' , '1990-01-01' , '男');insert into Student values('02' , '钱电' , '1990-12-21' , '男');insert into Student values('03' , '孙风' , '1990-12-20' , '男');insert into Student values('04' , '李云' , '1990-12-06' , '男');insert into Student values('05' , '周梅' , '1991-12-01' , '女');insert into Student values('06' , '吴兰' , '1992-01-01' , '女');insert into Student values('07' , '郑竹' , '1989-01-01' , '女');insert into Student values('09' , '张三' , '2017-12-20' , '女');insert into Student values('10' , '李四' , '2017-12-25' , '女');insert into Student values('11' , '李四' , '2012-06-06' , '女');insert into Student values('12' , '赵六' , '2013-06-13' , '女');insert into Student values('13' , '孙七' , '2014-06-01' , '女');

科目表 Course

create table Course(CId varchar(10),Cname nvarchar(10),TId varchar(10));insert into Course values('01' , '语文' , '02');insert into Course values('02' , '数学' , '01');insert into Course values('03' , '英语' , '03');**教师表 Teacher**

create table Teacher(TId varchar(10),Tname varchar(10));insert into Teacher values('01' , '张三');insert into Teacher values('02' , '李四');insert into Teacher values('03' , '王五');

成绩表 SC

create table SC(SId varchar(10),CId varchar(10),score decimal(18,1));insert into SC values('01' , '01' , 80);insert into SC values('01' , '02' , 90);insert into SC values('01' , '03' , 99);insert into SC values('02' , '01' , 70);insert into SC values('02' , '02' , 60);insert into SC values('02' , '03' , 80);insert into SC values('03' , '01' , 80);insert into SC values('03' , '02' , 80);insert into SC values('03' , '03' , 80);insert into SC values('04' , '01' , 50);insert into SC values('04' , '02' , 30);insert into SC values('04' , '03' , 20);insert into SC values('05' , '01' , 76);insert into SC values('05' , '02' , 87);insert into SC values('06' , '01' , 31);insert into SC values('06' , '03' , 34);insert into SC values('07' , '02' , 89);insert into SC values('07' , '03' , 98);

练习题目

  1. 查询" 01 “课程比” 02 "课程成绩高的学生的信息及课程分数

    SELECT s.*, a.score AS score_01, b.score AS score_02
FROM Student s
JOIN SC a ON s.SId = a.SId AND a.CId = '01'
JOIN SC b ON s.SId = b.SId AND b.CId = '02'
WHERE a.score > b.score;

  2. 查询同时存在" 01 “课程和” 02 "课程的情况

    SELECT s.*
FROM Student s
JOIN SC a ON s.SId = a.SId AND a.CId = '01'
JOIN SC b ON s.SId = b.SId AND b.CId = '02';

  3. 查询存在" 01 “课程但可能不存在” 02 "课程的情况(不存在时显示为 null )

    SELECT s.*, a.score AS score_01, b.score AS score_02
FROM Student s
JOIN SC a ON s.SId = a.SId AND a.CId = '01'
LEFT JOIN SC b ON s.SId = b.SId AND b.CId = '02';

  4. 查询不存在" 01 “课程但存在” 02 "课程的情况

    SELECT s.*
FROM Student s
JOIN SC b ON s.SId = b.SId AND b.CId = '02'
LEFT JOIN SC a ON s.SId = a.SId AND a.CId = '01'
WHERE a.SId IS NULL;

  5. 查询平均成绩大于等于 60 分的同学的学生编号和学生姓名和平均成绩

    SELECT s.SId, s.Sname, AVG(sc.score) AS avg_score
FROM Student s
JOIN SC sc ON s.SId = sc.SId
GROUP BY s.SId, s.Sname
HAVING avg_score >= 60;

  6. 查询在 SC 表存在成绩的学生信息

    SELECT DISTINCT s.*
FROM Student s
JOIN SC ON s.SId = SC.SId;

  7. 查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩(没成绩的显示为 null )

    SELECT s.SId, s.Sname, COUNT(sc.CId) AS total_courses, SUM(sc.score) AS total_score
FROM Student s
LEFT JOIN SC sc ON s.SId = sc.SId
GROUP BY s.SId, s.Sname;

  8. 查有成绩的学生信息

    SELECT s.*
FROM Student s
WHERE EXISTS (SELECT 1 FROM SC WHERE SC.SId = s.SId);

  9. 查询「李」姓老师的数量

    SELECT COUNT(*) FROM Teacher WHERE Tname LIKE '李%';

  10. 查询学过「张三」老师授课的同学的信息

    SELECT s.*
FROM Student s
JOIN SC ON s.SId = SC.SId
JOIN Course c ON SC.CId = c.CId
JOIN Teacher t ON c.TId = t.TId
WHERE t.Tname = '张三';

  11. 查询没有学全所有课程的同学的信息

    SELECT s.*
FROM Student s
WHERE s.SId NOT IN (SELECT SId FROM SC GROUP BY SId HAVING COUNT(DISTINCT CId) = (SELECT COUNT(*) FROM Course)
);

  12. 查询至少有一门课与学号为" 01 "的同学所学相同的同学的信

    SELECT DISTINCT s.*
FROM Student s
JOIN SC sc ON s.SId = sc.SId
WHERE sc.CId IN (SELECT CId FROM SC WHERE SId = '01') AND s.SId != '01';

  13. 查询和" 01 "号的同学学习的课程 完全相同的其他同学的信息

    SELECT s.*
FROM Student s
WHERE s.SId IN (SELECT SId FROM SC WHERE SId != '01'GROUP BY SIdHAVING GROUP_CONCAT(CId ORDER BY CId) = (SELECT GROUP_CONCAT(CId ORDER BY CId) FROM SC WHERE SId = '01')
);

  14. 查询没学过"张三"老师讲授的任一门课程的学生姓名

    SELECT Sname FROM Student
WHERE SId NOT IN (SELECT DISTINCT SC.SId FROM SC JOIN Course ON SC.CId = Course.CIdJOIN Teacher ON Course.TId = Teacher.TIdWHERE Teacher.Tname = '张三'
);

  15. 查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩

    SELECT s.SId, s.Sname, AVG(sc.score) AS avg_score
FROM Student s
JOIN SC sc ON s.SId = sc.SId
WHERE sc.score < 60
GROUP BY s.SId, s.Sname
HAVING COUNT(*) >= 2;

  16. 检索" 01 "课程分数小于 60，按分数降序排列的学生信息

    SELECT s.*, sc.score
FROM Student s
JOIN SC sc ON s.SId = sc.SId
WHERE sc.CId = '01' AND sc.score < 60
ORDER BY sc.score DESC;

  17. 按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩

    SELECT s.SId, s.Sname, GROUP_CONCAT(sc.CId, ':', sc.score) AS scores,AVG(sc.score) AS avg_score
FROM Student s
LEFT JOIN SC sc ON s.SId = sc.SId
GROUP BY s.SId, s.Sname
ORDER BY avg_score DESC;

  18. 查询各科成绩最高分、最低分和平均分：

    SELECT c.CId, c.Cname,MAX(sc.score) AS max_score,MIN(sc.score) AS min_score,AVG(sc.score) AS avg_score,COUNT(*) AS enroll,CONCAT(ROUND(SUM(CASE WHEN score >= 60 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS pass_rate,CONCAT(ROUND(SUM(CASE WHEN score BETWEEN 70 AND 80 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS medium_rate,CONCAT(ROUND(SUM(CASE WHEN score BETWEEN 80 AND 90 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS good_rate,CONCAT(ROUND(SUM(CASE WHEN score >= 90 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS excellent_rate
FROM SC sc
JOIN Course c ON sc.CId = c.CId
GROUP BY sc.CId
ORDER BY enroll DESC, c.CId;

  19. 以如下形式显示：课程 ID，课程 name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率,及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90,

    要求输出课程号和选修人数，查询结果按人数降序排列，若人数相同，按课程号升序排列

  20. 按各科成绩进行排序，并显示排名， Score 重复时保留名次空缺

    SELECT SId, CId, score,RANK() OVER (PARTITION BY CId ORDER BY score DESC) AS rank
FROM SC;

  21. 按各科成绩进行排序，并显示排名， Score 重复时合并名次

    SELECT SId, CId, score,DENSE_RANK() OVER (PARTITION BY CId ORDER BY score DESC) AS rank
FROM SC;

  22. 查询学生的总成绩，并进行排名，总分重复时保留名次空缺

    SELECT SId, total_score,RANK() OVER (ORDER BY total_score DESC) AS rank
FROM (SELECT SId, SUM(score) AS total_score FROM SC GROUP BY SId) t;

  23. 查询学生的总成绩，并进行排名，总分重复时不保留名次空缺

    SELECT SId, total_score,DENSE_RANK() OVER (ORDER BY total_score DESC) AS rank
FROM (SELECT SId, SUM(score) AS total_score FROM SC GROUP BY SId) t;

  24. 统计各科成绩各分数段人数：课程编号，课程名称，[100-85]，[85-70]，[70-60]，[60-0] 及所占百分比

    SELECT c.CId, c.Cname,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS `85-100`,SUM(CASE WHEN score BETWEEN 70 AND 84 THEN 1 ELSE 0 END) AS `70-84`,SUM(CASE WHEN score BETWEEN 60 AND 69 THEN 1 ELSE 0 END) AS `60-69`,SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) AS `<60`,CONCAT(ROUND(SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS `85-100%`,CONCAT(ROUND(SUM(CASE WHEN score BETWEEN 70 AND 84 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS `70-84%`,CONCAT(ROUND(SUM(CASE WHEN score BETWEEN 60 AND 69 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS `60-69%`,CONCAT(ROUND(SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) * 100.0 / COUNT(*), 2), '%') AS `<60%`
FROM SC sc
JOIN Course c ON sc.CId = c.CId
GROUP BY sc.CId;

  25. 查询各科成绩前三名的记录

    SELECT * FROM (SELECT *, ROW_NUMBER() OVER (PARTITION BY CId ORDER BY score DESC) AS rankFROM SC
) t WHERE rank <= 3;

  26. 查询每门课程被选修的学生数

    SELECT CId, COUNT(DISTINCT SId) AS num
FROM SC
GROUP BY CId;

  27. 查询出只选修两门课程的学生学号和姓名

    SELECT s.SId, s.Sname
FROM Student s
JOIN SC ON s.SId = SC.SId
GROUP BY s.SId
HAVING COUNT(*) = 2;

  28. 查询男生、女生人数

    SELECT Ssex, COUNT(*) FROM Student GROUP BY Ssex;

  29. 查询名字中含有「风」字的学生信息

    SELECT * FROM Student WHERE Sname LIKE '%风%';

  30. 查询同名同性学生名单，并统计同名人数

    SELECT Sname, Ssex, COUNT(*) AS count
FROM Student
GROUP BY Sname, Ssex
HAVING count > 1;

  31. 查询 1990 年出生的学生名单

    SELECT * FROM Student WHERE YEAR(Sage) = 1990;

  32. 查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号升序排列

    SELECT CId, AVG(score) AS avg_score
FROM SC
GROUP BY CId
ORDER BY avg_score DESC, CId;

  33. 查询平均成绩大于等于 85 的所有学生的学号、姓名和平均成绩

    SELECT s.SId, s.Sname, AVG(sc.score) AS avg_score
FROM Student s
JOIN SC sc ON s.SId = sc.SId
GROUP BY s.SId
HAVING avg_score >= 85;

  34. 查询课程名称为「数学」，且分数低于 60 的学生姓名和分数

    SELECT s.Sname, sc.score
FROM Student s
JOIN SC sc ON s.SId = sc.SId
JOIN Course c ON sc.CId = c.CId
WHERE c.Cname = '数学' AND sc.score < 60;

  35. 查询所有学生的课程及分数情况（存在学生没成绩，没选课的情况）

    SELECT s.SId, s.Sname, c.Cname, sc.score
FROM Student s
LEFT JOIN SC sc ON s.SId = sc.SId
LEFT JOIN Course c ON sc.CId = c.CId;

  36. 查询任何一门课程成绩在 70 分以上的姓名、课程名称和分数

    SELECT DISTINCT s.*
FROM Student s
JOIN SC ON s.SId = SC.SId
WHERE SC.score > 70;

  37. 查询不及格的课程

    SELECT * FROM SC WHERE score < 60;

  38. 查询课程编号为 01 且课程成绩在 80 分以上的学生的学号和姓名

    SELECT s.SId, s.Sname
FROM Student s
JOIN SC ON s.SId = SC.SId
WHERE SC.CId = '01' AND SC.score >= 80;

  39. 求每门课程的学生人数

    SELECT CId, COUNT(DISTINCT SId) FROM SC GROUP BY CId;

  40. 成绩不重复，查询选修「张三」老师所授课程的学生中，成绩最高的学生信息及其成绩

    SELECT s.*, sc.score
FROM SC sc
JOIN Course c ON sc.CId = c.CId
JOIN Teacher t ON c.TId = t.TId
JOIN Student s ON sc.SId = s.SId
WHERE t.Tname = '张三'
ORDER BY sc.score DESC
LIMIT 1;

  41. 成绩有重复的情况下，查询选修「张三」老师所授课程的学生中，成绩最高的学生信息及其成绩

    SELECT s.*, sc.score
FROM SC sc
JOIN Course c ON sc.CId = c.CId
JOIN Teacher t ON c.TId = t.TId
JOIN Student s ON sc.SId = s.SId
WHERE t.Tname = '张三' AND sc.score = (SELECT MAX(score) FROM SC JOIN Course ON SC.CId = Course.CId JOIN Teacher ON Course.TId = Teacher.TId WHERE Teacher.Tname = '张三'
);

  42. 查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩

    SELECT a.SId, a.CId, a.score
FROM SC a
JOIN SC b ON a.SId = b.SId AND a.CId <> b.CId AND a.score = b.score
GROUP BY a.SId, a.CId, a.score;

  43. 查询每门功成绩最好的前两名

    SELECT * FROM (SELECT *, ROW_NUMBER() OVER (PARTITION BY CId ORDER BY score DESC) AS rankFROM SC
) t WHERE rank <= 2;

  44. 统计每门课程的学生选修人数（超过 5 人的课程才统计）。

    SELECT CId, COUNT(*) AS num
FROM SC
GROUP BY CId
HAVING num > 5;

  45. 检索至少选修两门课程的学生学号

    SELECT SId FROM SC GROUP BY SId HAVING COUNT(*) >= 2;

  46. 查询选修了全部课程的学生信息

    SELECT s.*
FROM Student s
WHERE (SELECT COUNT(DISTINCT CId) FROM SC WHERE SC.SId = s.SId) = (SELECT COUNT(*) FROM Course);

  47. 查询各学生的年龄，只按年份来算

    SELECT SId, YEAR(NOW()) - YEAR(Sage) AS age FROM Student;

  48. 按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一

    SELECT SId, TIMESTAMPDIFF(YEAR, Sage, NOW()) - (DATE_FORMAT(NOW(), '%m%d') < DATE_FORMAT(Sage, '%m%d')) AS age
FROM Student;

  49. 查询本周过生日的学生

    SELECT * FROM Student
WHERE WEEKOFYEAR(Sage) = WEEKOFYEAR(NOW());

  50. 查询下周过生日的学生

    SELECT * FROM Student
WHERE WEEKOFYEAR(Sage) = WEEKOFYEAR(NOW()) + 1;

  51. 查询本月过生日的学生

    SELECT * FROM Student WHERE MONTH(Sage) = MONTH(NOW());

  52. 查询下月过生日的学生

    SELECT * FROM Student 
WHERE MONTH(Sage) = MONTH(NOW()) + 1 OR (MONTH(NOW()) = 12 AND MONTH(Sage) = 1);

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