MySQL测试

系统初始了以下脚本数据

向student表插入记录的INSERT语句如下：

INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区');INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区');INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市');INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市');INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市');INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市');

向score表插入记录的INSERT语句如下：

INSERT INTO score VALUES(NULL,901, '计算机',98);INSERT INTO score VALUES(NULL,901, '英语', 80);INSERT INTO score VALUES(NULL,902, '计算机',65);INSERT INTO score VALUES(NULL,902, '中文',88);INSERT INTO score VALUES(NULL,903, '中文',95);INSERT INTO score VALUES(NULL,904, '计算机',70);INSERT INTO score VALUES(NULL,904, '英语',92);INSERT INTO score VALUES(NULL,905, '英语',94);INSERT INTO score VALUES(NULL,906, '计算机',90);INSERT INTO score VALUES(NULL,906, '英语',85);

1、创建student和score表语句

CREATE TABLE student(id INT(10) AUTO_INCREMENT PRIMARY KEY,name VARCHAR(20) NOT NULL,sex VARCHAR(4),birth YEAR,department VARCHAR(20) NOT NULL,address VARCHAR(50));CREATE TABLE score(id INT(10) AUTO_INCREMENT PRIMARY KEY,stu_id INT(10) NOT NULL,c_name VARCHAR(20),grade INT(10));

Student 表

Score 表

2.查询student表的所有记录

SELECT * FROM student;

3.查询student表的第二条到第四条记录

SELECT * FROM student LIMIT 1,3;

4.从student表查询所有学生的学号（id）、姓名（name）和院系（department）的信息

SELECT id,name,department FROM student;

5.从student表中查询计算机系和英语系的学生的信息（用IN关键字）

SELECT * FROM student WHERE department IN ('计算机系','英语系');

6.从student表中查询年龄22~26岁的学生的信息（用 BETWEEN AND）

SELECT * FROM student WHERE (YEAR(NOW())-birth) BETWEEN 22 AND 26;

7.从student表中查询每个院系有多少人

SELECT department AS '学院',COUNT(*) AS '总人数'FROM student GROUP BY department;

8、从score表中查询每个科目的最高分

SELECT c_name AS '课程',MAX(grade) AS '最高分'FROM score GROUP BY c_name;

9、查询李四的考试科目（c_name）和考试成绩（grade）

#方法一SELECTc.c_name AS '课程',c.grade AS '成绩'FROM score AS cLEFT JOIN student AS s ON c.stu_id = s.idWHERE s.name = '李四';#方法二SELECT c_name AS '课程',grade AS '成绩'FROM scoreWHERE stu_id=(SELECT id FROM student WHERE name='李四');

10、用连接的方式查询所有学生的信息和考试信息

SELECT * FROM score AS cLEFT JOIN student AS sON s.id=c.stu_id;

11、计算每个学生的总成绩

SELECT s.id AS '学号',s.name AS '姓名',SUM(grade) AS '总成绩'FROM score AS cLEFT JOIN student AS s ON s.id=c.stu_idGROUP BY s.id;

12、计算每个考试科目的平均成绩

SELECT c_name AS '课程',AVG(grade) AS '平均成绩'FROM score GROUP BY c_name;

13、查询计算机成绩低于95的学生信息

#方法一SELECT * FROM score AS cLEFT JOIN student AS s ON s.id=c.stu_idWHERE c.c_name='计算机' AND grade < 95;#方法二SELECT * FROM student WHERE id IN(SELECT stu_id FROM score WHERE c_name='计算机' AND grade<95);

14、查询同时参加计算机和英语考试的学生的信息

#方法一SELECT * FROM student WHERE id=ANY(SELECT stu_id FROM score WHERE stu_id IN(SELECT stu_id FROM score WHERE c_name='计算机')AND c_name='英语')#方法二SELECT a.* FROM student a,score b,score cWHERE a.id=b.stu_idAND b.c_name='计算机'AND a.id=c.stu_idAND c.c_name='英语'

15、将计算机考试成绩按从高到低进行排序

SELECT stu_id AS '学号',grade AS '考试成绩' FROM scoreWHERE c_name='计算机'ORDER BY grade DESC;

16、从student表和score表中查询出学生的学号，然后合并查询结果

SELECT id FROM studentUNIONSELECT stu_id FROM score;

17、查询姓张或者姓王的同学的姓名、院系和考试科目及成绩

SELECT s.name AS '姓名',s.department AS '院系',c.c_name AS '考试科目',c.grade AS '成绩'FROM score AS c LEFT JOIN student AS s ON s.id=c.stu_idWHERE s.name LIKE '王%' OR s.name LIKE '张%';

18、查询都是湖南的学生的姓名、年龄、院系和考试科目及成绩

SELECT s.name AS '姓名',YEAR(NOW())-birth AS '年龄',s.department AS '院系',c.c_name AS '考试科目',c.grade AS '成绩'FROM score AS c LEFT JOIN student AS s ON s.id=c.stu_idWHERE s.address LIKE '湖南%';