SQL (student-score表)源代码

– 创建学生表
CREATE TABLE student(
id INT(10)NOT NULL UNIQUE PRIMARY KEY,
name VARCHAR(20)NOT NULL,
sex VARCHAR(4),
Birth YEAR,
Departme VARCHAR(20)NOT NULL,
Address VARCHAR(50)
);

– 创建score表格
CREATE TABLE Score(
id INT(10)NOT NULL UNIQUE AUTO_INCREMENT PRIMARY KEY,
Stu_id INT(10) NOT NULL,
C_name VARCHAR(20),
Grade INT(10)
);

– 为student表插入记录
INSERT INTO student VALUES(901,’张老大’,’男’,1985,’计算机系’,’北京海定区’);
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’);

– 为score表插入记录
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);

– 查询student中所有的信息
SELECT*FROM student

– 查询student表的第二条记录到第四条记录
SELECT*FROM student LIMIT 1,3

– 从student表中查询出所有学生的id,name,department的信息
SELECT id,name,Departme FROM student

– 从student表中查询出计算机系和英语系的学生信息
SELECT*FROM student WHERE Departme IN(‘计算机系’,’英语系’);

– 从student表中查询出18-22岁学生的信息
SELECT
id,name,sex,2013-Birth AS age,Departme,Address
FROM student
WHERE 2013-Birth BETWEEN 18 AND 22;

– 从student表中查询每个院系有多少人
SELECT Departme,COUNT(*)FROM student GROUP BY Departme

–从score表中查询每个科目的最高分
SELECT C_name,MAX(Grade)FROM Score GROUP BY C_name;

–查询李四的考试科目和成绩
SELECT C_name,Grade
FROM Score
WHERE stu_id=(SELECT id FROM student WHERE name=’李四’);

– 用连接的方式查询所有学生的信息和考试信息
SELECT*FROM student,Score
WHERE student.id=score.stu_id

– 计算出每个学生的总成绩
SELECT student.id,name,SUM(Grade)FROM student,Score
WHERE student.id=Score.stu_id
GROUP BY id;

– 计算每个考试科目的平均成绩
SELECT C_name,AVG(Grade)FROM score GROUP BY C_name

–查询计算机成绩低于95分的学生信息
SELECT*FROM student
WHERE id IN
(SELECT stu_id FROM Score
WHERE C_name=”计算机”AND Grade<95);

– 查询同时参加计算机和英语考试的学生信息
SELECT a.* FROM student a,Score b,Score c
WHERE a.id=b.Stu_id
AND b.C_name=’计算机’
AND a.id=c.Stu_id
AND c.C_name=’英语’;

– 将计算机考试成绩按从高到低进行排序
SELECT Stu_id,Grade FROM Score
WHERE C_name=’计算机’
ORDER BY Grade DESC;

– 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 student
UNION
SELECT
Stu_id FROM Score

– 查询姓张的或者姓王的同学的姓名,院系,和考试科目及成绩
SELECT student.id,name,C_name,Grade
FROM student,Score
WHERE (name LIKE ‘张‘OR name LIKE’王‘)
AND
student.id=Score.Stu_id;

– 查询都是湖南的姓名而定姓名,年龄,院系和考试科目及成绩
SELECT student.id,name,Departme,address,C_name,Grade
FROM student,Score
WHERE address LIKE’湖南%’AND
student.id=Score.stu_id