关系数据库语言sql题答案大全，关系数据库语言sql题答案

关系数据库语言 SQL 题答案大全

一、引言

关系数据库语言 SQL（Structured Query Language）是一种用于管理关系型数据库的标准语言，它提供了一种强大而灵活的方式来查询、插入、更新和删除数据，以及定义数据库结构和约束，在实际应用中，我们经常会遇到各种 SQL 题，需要运用 SQL 的知识和技能来解决，本文将提供一些常见的 SQL 题及其答案，帮助读者更好地理解和掌握 SQL 语言。

二、SQL 题及答案

1、查询学生表中所有学生的信息

SELECT * FROM students;

2、查询学生表中年龄大于等于 20 岁的学生信息

SELECT * FROM students WHERE age >= 20;

3、查询学生表中姓王的学生信息

SELECT * FROM students WHERE name LIKE '王%';

4、查询学生表中成绩大于等于 80 分的学生信息，并按照成绩降序排列

SELECT * FROM students WHERE score >= 80 ORDER BY score DESC;

5、查询学生表中成绩在 60 分到 80 分之间的学生信息

SELECT * FROM students WHERE score BETWEEN 60 AND 80;

6、查询学生表中没有选修课程的学生信息

SELECT * FROM students WHERE student_id NOT IN (SELECT student_id FROM course_students);

7、查询学生表中选修了课程编号为 1 的学生信息

SELECT * FROM students WHERE student_id IN (SELECT student_id FROM course_students WHERE course_id = 1);

8、查询学生表中选修了课程编号为 1 且成绩大于等于 80 分的学生信息

SELECT * FROM students WHERE student_id IN (SELECT student_id FROM course_students WHERE course_id = 1 AND score >= 80);

9、查询学生表中选修了课程编号为 1 或课程编号为 2 的学生信息

SELECT * FROM students WHERE student_id IN (SELECT student_id FROM course_students WHERE course_id = 1) OR student_id IN (SELECT student_id FROM course_students WHERE course_id = 2);

10、查询学生表中选修了课程编号为 1 且成绩大于等于 80 分，或者选修了课程编号为 2 且成绩大于等于 90 分的学生信息

SELECT * FROM students WHERE (student_id IN (SELECT student_id FROM course_students WHERE course_id = 1 AND score >= 80)) OR (student_id IN (SELECT student_id FROM course_students WHERE course_id = 2 AND score >= 90));

11、查询学生表中选修了课程编号为 1 的学生人数

SELECT COUNT(*) FROM course_students WHERE course_id = 1;

12、查询学生表中所有学生的平均成绩

SELECT AVG(score) FROM students;

13、查询学生表中成绩最高的学生信息

SELECT * FROM students WHERE score = (SELECT MAX(score) FROM students);

14、查询学生表中成绩最低的学生信息

SELECT * FROM students WHERE score = (SELECT MIN(score) FROM students);

15、查询学生表中成绩排名前 10 的学生信息

SELECT * FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY score DESC) AS row_num FROM students) AS temp WHERE row_num <= 10;

16、查询学生表中成绩排名第 11 到第 20 的学生信息

SELECT * FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY score DESC) AS row_num FROM students) AS temp WHERE row_num > 10 AND row_num <= 20;

17、查询学生表中成绩排名在第 11 到第 20 之间的学生信息

SELECT * FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY score DESC) AS row_num FROM students) AS temp WHERE row_num BETWEEN 11 AND 20;

18、查询学生表中成绩排名在第 11 到第 20 之间的学生人数

SELECT COUNT(*) FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY score DESC) AS row_num FROM students) AS temp WHERE row_num BETWEEN 11 AND 20;

19、查询学生表中成绩排名在第 11 到第 20 之间的学生的平均成绩

SELECT AVG(score) FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY score DESC) AS row_num FROM students) AS temp WHERE row_num BETWEEN 11 AND 20;

20、查询学生表中成绩排名在第 11 到第 20 之间的学生的总成绩

SELECT SUM(score) FROM (SELECT *, ROW_NUMBER() OVER (ORDER BY score DESC) AS row_num FROM students) AS temp WHERE row_num BETWEEN 11 AND 20;

三、总结

通过以上 SQL 题及其答案的学习，我们可以更好地掌握 SQL 语言的基本语法和常用操作，在实际应用中，我们还需要根据具体的需求和场景，灵活运用 SQL 语言的各种功能和技巧，以实现高效的数据管理和查询，我们也需要注意 SQL 语言的安全性和性能优化，以确保数据库的稳定和可靠运行。

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