mysql综合测试

DROP DATABASE IF EXISTS student;
CREATE DATABASE student;
USE student;

CREATE TABLE student(
	studentno VARCHAR(10) NOT NULL PRIMARY KEY,
	studentname VARCHAR(20) NOT NULL,
	loginpwd VARCHAR(8) NOT NULL,
	sex CHAR(1) ,
	majorid INT NOT NULL REFERENCES grade(majorid),
	phone VARCHAR(11),
	email VARCHAR(20) ,
	borndate DATETIME
);

CREATE TABLE major(
	majorid INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
	majorname VARCHAR(20) NOT  NULL

);
CREATE TABLE result(
	id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
	studentno VARCHAR(10) NOT NULL REFERENCES student(studentno),
	score DOUBLE
);


INSERT INTO major VALUES(NULL,'javaee');
INSERT INTO major VALUES(NULL,'html5');
INSERT INTO major VALUES(NULL,'android');


INSERT INTO student VALUES('S001','张三封','8888','男',1,'13288886666','[email protected]','1966-9-1');
INSERT INTO student VALUES('S002','殷天正','8888','男',1,'13888881234','[email protected]','1976-9-2');
INSERT INTO student VALUES('S003','周伯通','8888','男',2,'13288886666','[email protected]','1986-9-3');
INSERT INTO student VALUES('S004','张翠山','8888','男',1,'13288886666',NULL,'1995-9-4');
INSERT INTO student VALUES('S005','小小张','8888','女',3,'13288885678','[email protected]','1990-9-5');

INSERT INTO student VALUES('S006','张无忌','8888','男',2,'13288886666','[email protected]','1998-8-9');
INSERT INTO student VALUES('S007','赵敏','0000','女',1,'13288880987','[email protected]','1998-6-9');
INSERT INTO student VALUES('S008','周芷若','6666','女',1,'13288883456','[email protected]','1996-7-9');
INSERT INTO student VALUES('S009','殷素素','8888','女',1,'13288886666','[email protected]','1986-1-9');
INSERT INTO student VALUES('S010','宋远桥','6666','男',3,'1328888890','[email protected]','1996-2-9');


INSERT INTO student VALUES('S011','杨不悔','6666','女',2,'13288882345',NULL,'1995-9-9');
INSERT INTO student VALUES('S012','杨逍','9999','男',1,'13288885432',NULL,'1976-9-9');
INSERT INTO student VALUES('S013','纪晓芙','9999','女',3,'13288888765',NULL,'1976-9-9');
INSERT INTO student VALUES('S014','谢逊','9999','男',1,'13288882211',NULL,'1946-9-9');
INSERT INTO student VALUES('S015','宋青书','9999','男',3,'13288889900',NULL,'1976-6-8');



INSERT INTO result VALUES(NULL,'s001',100);
INSERT INTO result VALUES(NULL,'s002',90);
INSERT INTO result VALUES(NULL,'s003',80);

INSERT INTO result VALUES(NULL,'s004',70);
INSERT INTO result VALUES(NULL,'s005',60);
INSERT INTO result VALUES(NULL,'s006',50);
INSERT INTO result VALUES(NULL,'s006',40);
INSERT INTO result VALUES(NULL,'s005',95);
INSERT INTO result VALUES(NULL,'s006',88);

#一、查询每个专业的学生人数
SELECT majorid,COUNT(*)
FROM student
GROUP BY majorid;

#二、查询参加考试的学生中，每个学生的平均分、最高分
SELECT AVG(score),MAX(score),studentno
FROM result
GROUP BY studentno;

#三、查询姓张的每个学生的最低分大于60的学号、姓名
SELECT s.studentno,s.`studentname`,MIN(score)
FROM student s
JOIN result r
ON s.`studentno`=r.`studentno`
WHERE s.`studentname` LIKE '张%'
GROUP BY s.`studentno`
HAVING MIN(score)>60;
#四、查询每个专业生日在“1988-1-1”后的学生姓名、专业名称

SELECT m.`majorname`,s.`studentname`
FROM student s
JOIN major m
ON m.`majorid`=s.`majorid`
WHERE DATEDIFF(borndate,'1988-1-1')>0
GROUP BY m.`majorid`;


#五、查询每个专业的男生人数和女生人数分别是多少

SELECT COUNT(*),sex,majorid
FROM student
GROUP BY sex,majorid;
#六、查询专业和张翠山一样的学生的最低分
#①查询张翠山的专业编号
SELECT majorid
FROM student
WHERE studentname = '张翠山'

#②查询编号=①的所有学生编号
SELECT studentno
FROM student
WHERE majorid=(
	SELECT majorid
	FROM student
	WHERE studentname = '张翠山'

)
#②查询最低分
SELECT MIN(score)
FROM result
WHERE studentno IN(

	SELECT studentno
	FROM student
	WHERE majorid=(
		SELECT majorid
		FROM student
		WHERE studentname = '张翠山'

	)
)

#七、查询大于60分的学生的姓名、密码、专业名

SELECT studentname,loginpwd,majorname
FROM student s
JOIN major m ON s.majorid=  m.majorid
JOIN result r ON s.studentno=r.studentno
WHERE r.score>60;
#八、按邮箱位数分组，查询每组的学生个数
SELECT COUNT(*),LENGTH(email)
FROM student
GROUP BY LENGTH(email);
#九、查询学生名、专业名、分数

SELECT studentname,score,majorname
FROM student s
JOIN major m ON s.majorid=  m.majorid
LEFT JOIN result r ON s.studentno=r.studentno


#十、查询哪个专业没有学生，分别用左连接和右连接实现
#左
SELECT m.`majorid`,m.`majorname`,s.`studentno`
FROM major m
LEFT JOIN student s ON m.`majorid` = s.`majorid`
WHERE s.`studentno` IS NULL;

#右
SELECT m.`majorid`,m.`majorname`,s.`studentno`
FROM student s
RIGHT JOIN  major m ON m.`majorid` = s.`majorid`
WHERE s.`studentno` IS NULL;
#十一、查询没有成绩的学生人数

SELECT COUNT(*)
FROM student s
LEFT JOIN result r ON s.`studentno` = r.`studentno`
WHERE r.`id` IS NULL