SQL (student-score表)源代碼

– 創建學生表
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)
);

– 創建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)
);

– 爲student表插入記錄
INSERT INTO student VALUES(901,’張老大’,’男’,1985,’計算機系’,’北京海定區’);
INSERT INTO student VALUES(902,’張老二’,’男’,1986,’中文系’,’北京市昌平區’);
INSERT INTO student VALUES(903,’張三’,’女’,1990,’中文系’,’湖南省永州市’);
INSERT INTO student VALUES(904,’李四’,’男’,1990,’英語系’,’遼寧省阜新市’);
INSERT INTO student VALUES(905,’王五’,’女’,1991,’英語系’,’福建省廈門市’);
INSERT INTO student VALUES(906,’王六’,’男’,1988,’計算機系’,’湖南省衡陽市’);

– 爲score表插入記錄
INSERT INTO Score VALUES(NULL,901,’計算機’,98);
INSERT INTO Score VALUES(NULL,901,’英語’,80);
INSERT INTO Score VALUES(NULL,902,’計算機’,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,’計算機’,70);
INSERT INTO Score VALUES(NULL,904,’英語’,92);
INSERT INTO Score VALUES(NULL,905,’英語’,94);
INSERT INTO Score VALUES(NULL,906,’計算機’,90);
INSERT INTO Score VALUES(NULL,906,’英語’,85);

– 查詢student中所有的信息
SELECT*FROM student

– 查詢student表的第二條記錄到第四條記錄
SELECT*FROM student LIMIT 1,3

– 從student表中查詢出所有學生的id,name,department的信息
SELECT id,name,Departme FROM student

– 從student表中查詢出計算機系和英語系的學生信息
SELECT*FROM student WHERE Departme IN(‘計算機系’,’英語系’);

– 從student表中查詢出18-22歲學生的信息
SELECT
id,name,sex,2013-Birth AS age,Departme,Address
FROM student
WHERE 2013-Birth BETWEEN 18 AND 22;

– 從student表中查詢每個院系有多少人
SELECT Departme,COUNT(*)FROM student GROUP BY Departme

–從score表中查詢每個科目的最高分
SELECT C_name,MAX(Grade)FROM Score GROUP BY C_name;

–查詢李四的考試科目和成績
SELECT C_name,Grade
FROM Score
WHERE stu_id=(SELECT id FROM student WHERE name=’李四’);

– 用連接的方式查詢所有學生的信息和考試信息
SELECT*FROM student,Score
WHERE student.id=score.stu_id

– 計算出每個學生的總成績
SELECT student.id,name,SUM(Grade)FROM student,Score
WHERE student.id=Score.stu_id
GROUP BY id;

– 計算每個考試科目的平均成績
SELECT C_name,AVG(Grade)FROM score GROUP BY C_name

–查詢計算機成績低於95分的學生信息
SELECT*FROM student
WHERE id IN
(SELECT stu_id FROM Score
WHERE C_name=”計算機”AND Grade<95);

– 查詢同時參加計算機和英語考試的學生信息
SELECT a.* FROM student a,Score b,Score c
WHERE a.id=b.Stu_id
AND b.C_name=’計算機’
AND a.id=c.Stu_id
AND c.C_name=’英語’;

– 將計算機考試成績按從高到低進行排序
SELECT Stu_id,Grade FROM Score
WHERE C_name=’計算機’
ORDER BY Grade DESC;

– 從student表和score表中查詢出學生的學號,然後合併查詢結果
SELECT
id
FROM student
UNION
SELECT
Stu_id FROM Score

– 查詢姓張的或者姓王的同學的姓名,院系,和考試科目及成績
SELECT student.id,name,C_name,Grade
FROM student,Score
WHERE (name LIKE ‘張‘OR name LIKE’王‘)
AND
student.id=Score.Stu_id;

– 查詢都是湖南的姓名而定姓名,年齡,院系和考試科目及成績
SELECT student.id,name,Departme,address,C_name,Grade
FROM student,Score
WHERE address LIKE’湖南%’AND
student.id=Score.stu_id