✅作者简介：热爱国学的Java后端开发者，修心和技术同步精进。
🍎个人主页：乐趣国学的博客
🍊个人信条：不迁怒，不贰过。小知识，大智慧。
目录
1、创建数据库
2、使用数据库
3、创建数据表
【3.1】创建学生信息表student
【3.2】创建教师信息表teacher
【3.3】创建课程表course
【3.4】创建成绩表score
4、添加数据
【4.1】向学生student表添加数据
【4.2】向教师信息teacher表添加数据
【4.3】向课程course表添加数据
【4.4】向成绩score表添加数据
5、查询数据练习
1、创建数据库
CREATE DATABASE IF NOT EXISTS `examination`;
2、使用数据库
USE examination;
3、创建数据表
【3.1】创建学生信息表student
CREATE TABLE IF NOT EXISTS `student` (
`sno` VARCHAR (20) NOT NULL PRIMARY KEY COMMENT '学号',
`sname` VARCHAR (20) NOT NULL COMMENT '姓名',
`ssex` VARCHAR (20) NOT NULL COMMENT '性别',
`sbirthday` DATETIME COMMENT '出生日期',
`class` VARCHAR (20) COMMENT '班级'
) ;
【3.2】创建教师信息表teacher
CREATE TABLE IF NOT EXISTS `teacher` (
`tno` VARCHAR (20) NOT NULL PRIMARY KEY COMMENT '教师编号',
`tname` VARCHAR (20) NOT NULL COMMENT '姓名',
`tsex` VARCHAR (20) NOT NULL COMMENT '性别',
`tbirthday` DATETIME COMMENT '出生日期',
`prof` VARCHAR (20) COMMENT '职称',
`depart` VARCHAR (20) NOT NULL COMMENT '科系'
) ;
【3.3】创建课程表course
CREATE TABLE IF NOT EXISTS `course` (
`cno` VARCHAR (20) NOT NULL PRIMARY KEY COMMENT '课程编号',
`cname` VARCHAR (20) NOT NULL COMMENT '课程名称',
`tno` VARCHAR (20) NOT NULL COMMENT '授课教师编号',
CONSTRAINT fk_course_tno FOREIGN KEY (`tno`) REFERENCES `teacher` (`tno`)
) ;
【3.4】创建成绩表score
CREATE TABLE IF NOT EXISTS `score` (
`sno` VARCHAR (20) NOT NULL COMMENT '学生学号',
`cno` VARCHAR (20) NOT NULL COMMENT '课程编号',
`degree` NUMERIC (4, 1) COMMENT '成绩',
CONSTRAINT fk_score_sno FOREIGN KEY (`sno`) REFERENCES `student` (`sno`),
CONSTRAINT fk_score_cno FOREIGN KEY (`cno`) REFERENCES `course` (`cno`)
) ;
4、添加数据
【4.1】向学生student表添加数据
INSERT INTO student (sno,sname,ssex,sbirthday,class) VALUES (108 ,'曾华'
,'男' ,'1977-09-01','95033');
INSERT INTO student (sno,sname,ssex,sbirthday,class) VALUES (105 ,'匡明'
,'男' ,'1975-10-02','95031');
INSERT INTO student (sno,sname,ssex,sbirthday,class) VALUES (107 ,'王丽'
,'女' ,'1976-01-23','95033');
INSERT INTO student (sno,sname,ssex,sbirthday,class) VALUES (101 ,'李军'
,'男' ,'1976-02-20','95033');
INSERT INTO student (sno,sname,ssex,sbirthday,class) VALUES (109 ,'王芳'
,'女' ,'1975-02-10','95031');
INSERT INTO student (sno,sname,ssex,sbirthday,class) VALUES (103 ,'陆君'
,'男' ,'1974-06-03','95031');
【4.2】向教师信息teacher表添加数据
INSERT INTO teacher(tno,tname,tsex,tbirthday,prof,depart)
VALUES (804,'李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO teacher(tno,tname,tsex,tbirthday,prof,depart)
VALUES (856,'张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO teacher(tno,tname,tsex,tbirthday,prof,depart)
VALUES (825,'王萍','女','1972-05-05','助教','计算机系');
INSERT INTO teacher(tno,tname,tsex,tbirthday,prof,depart)
VALUES (831,'刘冰','女','1977-08-14','助教','电子工程系');
【4.3】向课程course表添加数据
INSERT INTO course(cno,cname,tno)VALUES ('3-105' ,'计算机导论',825);
INSERT INTO course(cno,cname,tno)VALUES ('3-245' ,'操作系统' ,804);
INSERT INTO course(cno,cname,tno)VALUES ('6-166' ,'数字电路' ,856);
INSERT INTO course(cno,cname,tno)VALUES ('9-888' ,'高等数学' ,831);【4.4】向成绩score表添加数据
INSERT INTO score(sno,cno,degree)VALUES (103,'3-245',86);
INSERT INTO score(sno,cno,degree)VALUES (105,'3-245',75);
INSERT INTO score(sno,cno,degree)VALUES (109,'3-245',68);
INSERT INTO score(sno,cno,degree)VALUES (103,'3-105',92);
INSERT INTO score(sno,cno,degree)VALUES (105,'3-105',88);
INSERT INTO score(sno,cno,degree)VALUES (109,'3-105',76);
INSERT INTO score(sno,cno,degree)VALUES (101,'3-105',64);
INSERT INTO score(sno,cno,degree)VALUES (107,'3-105',91);
INSERT INTO score(sno,cno,degree)VALUES (108,'3-105',78);
INSERT INTO score(sno,cno,degree)VALUES (101,'6-166',85);
INSERT INTO score(sno,cno,degree)VALUES (107,'6-166',79);
INSERT INTO score(sno,cno,degree)VALUES (108,'6-166',81);
5、查询数据练习
#1、 查询student表中的所有记录的sname、ssex和class列。
SELECT sname,ssex,class FROM student;#2、 查询教师所有的单位即不重复的depart列。
SELECT DISTINCT depart FROM teacher;#3、 查询student表的所有记录。
SELECT * FROM student;#4、 查询score表中成绩在60到80之间的所有记录。
#方式1
SELECT * FROM score WHERE degree BETWEEN 60 AND 80;
#方式2
SELECT * FROM score WHERE degree>=60 AND degree<=80;#5、 查询score表中成绩为85，86或88的记录。
#方式1
SELECT * FROM score WHERE degree=85 OR degree=86 OR degree=88;
#方式2
SELECT * FROM score WHERE degree IN ('85','86','88');#6、 查询student表中“95031”班或性别为“女”的同学记录。
SELECT * FROM student WHERE class='95031' OR ssex='女';#7、 以class降序查询student表的所有记录。
SELECT * FROM student ORDER BY class DESC;#8、 以cno升序、degree降序查询score表的所有记录。
SELECT * FROM score ORDER BY cno ASC,degree DESC;#9、 查询“95031”班的学生人数。
SELECT COUNT(*) FROM student WHERE class='95031';#10、 查询score表中的最高分的学生学号和课程号。（子查询或者排序）
SELECT sno,cno FROM score WHERE degree=(SELECT MAX(degree) FROM score);#11、 查询每门课的平均成绩。
SELECT cno,AVG(degree) AS 平均分 FROM score GROUP BY cno;#12、查询score表中至少有5名学生选修的并以3开头的课程的平均分数。
SELECT AVG(degree ) FROM score WHERE cno LIKE '3%' GROUP BY cno HAVING COUNT(cno)>4;#13、查询分数大于70，小于90的sno列。
SELECT sno FROM score WHERE degree >70 AND degree<90;#14、查询所有学生的sname、cno和degree列。
SELECT sname,cno,degree FROM student JOIN score ON student.sno=score.sno;#15、查询所有学生的sno、cname和degree列。
SELECT sno,cname,degree FROM score JOIN course ON course.cno=score.cno;#16、查询所有学生的sname、cname和degree列
SELECT student.sname,cname,degree FROM student JOIN score ON student.sno=score.sno JOIN course ON course.cno=score.cno;#17、 查询“95033”班学生的平均分。
#方式1
SELECT AVG(degree) FROM score WHERE sno IN (SELECT sno FROM student WHERE class='95033');
#方式2
SELECT AVG(degree) FROM score,student WHERE student.sno=score.sno AND class='95033';#18、 假设使用如下命令建立了一个grade表：
CREATE TABLE IF NOT EXISTS `grade` (
`low` INT (3) COMMENT '底限',
`upp` INT (3) COMMENT '上限',
`rank` CHAR(1) COMMENT '等级'
) ;#向grade表中添加数据
INSERT INTO grade VALUES(90,100,'A');
INSERT INTO grade VALUES(80,89,'B');
INSERT INTO grade VALUES(70,79,'C');
INSERT INTO grade VALUES(60,69,'D');
INSERT INTO grade VALUES(0,59,'E');#现查询所有同学的sno、cno和rank列。
#方式1
SELECT sno,cno,degree,rank FROM grade JOIN score ON score.degree BETWEEN low AND upp;
#方式2
SELECT sno,cno,degree,rank FROM score,grade WHERE degree BETWEEN low AND upp;#19、 查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
SELECT * FROM student,score WHERE score.cno='3-105' AND student.sno=score.sno AND score.degree>(SELECT degree FROM score WHERE cno='3-105' AND sno='109');#20、查询score中选学多门课程的同学中分数为非最高分成绩的记录。
SELECT * FROM score a WHERE degree <(SELECT MAX(degree) FROM score b WHERE a.cno=b.cno) AND sno IN(SELECT sno FROM score GROUP BY sno HAVING COUNT(*)>1);#21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
SELECT * FROM student,score WHERE student.sno=score.sno AND score.degree>(SELECT degree FROM score WHERE cno='3-105' AND sno='109');#22、查询和学号为107的同学同年出生的所有学生的sno、sname和sbirthday列。
SELECT sno,sname,sbirthday FROM student WHERE YEAR(student.sbirthday)=(SELECT YEAR(sbirthday) FROM student WHERE sno='107');#23、查询“张旭“教师任课的学生成绩。
SELECT degree FROM score,teacher,course WHERE teacher.tname='张旭' AND teacher.tno=course.tno AND course.cno=score.cno;
SELECT sno,cno,degree FROM score WHERE cno IN (SELECT cno FROM course WHERE tno IN (SELECT tno FROM teacher WHERE tname='张旭'));#24、查询选修某课程的同学人数多于5人的教师姓名。
SELECT tname FROM teacher WHERE tno IN (SELECT tno FROM course WHERE cno IN (SELECT cno FROM score GROUP BY cno HAVING COUNT(*)>5) )#25、查询95033班和95031班全体学生的记录。
SELECT * FROM student WHERE class='95033' OR class='95031'#26、 查询存在有85分以上成绩的课程cno.
SELECT DISTINCT cno FROM score WHERE degree>85#27、查询出“计算机系“教师所教课程的成绩表。
SELECT sno,cno ,degree FROM score WHERE cno IN (SELECT cno FROM course WHERE tno IN (SELECT tno FROM teacher WHERE depart='计算机系'))#28、查询“计算机系”与“电子工程系“不同职称的教师的tname和prof。
SELECT tname,prof FROM teacher a WHERE prof NOT IN(SELECT prof FROM teacher b WHERE a.depart!=b.depart)#29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的cno、sno和degree,并按degree从高到低次序排序。
SELECT * FROM score WHERE cno='3-105' AND degree >ANY(SELECT degree FROM score WHERE cno='3-245')#30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的cno、sno和degree.
SELECT * FROM score a WHERE a.cno = '3-105' AND a.degree > ( SELECT b.degree FROM score b WHERE cno = '3-245' AND a.sno = b.sno )#31、 查询所有教师和同学的name、sex和birthday.
SELECT DISTINCT sname AS NAME,ssex AS sex,sbirthday AS birthday FROM student UNION SELECT DISTINCT tname AS NAME,tsex AS sex,Tbirthday AS birthday FROM teacher#32、查询所有“女”教师和“女”同学的name、sex和birthday.
SELECT DISTINCT sname AS NAME,ssex AS sex,sbirthday AS birthday FROM student WHERE ssex='女' UNION SELECT DISTINCT tname AS NAME,tsex AS sex,Tbirthday AS birthday FROM teacher WHERE tsex='女'#33、 查询成绩比该课程平均成绩低的同学的成绩表。
SELECT sno,cno,degree FROM score a WHERE a.degree<(SELECT AVG(degree) FROM score b WHERE a.cno=b.cno)#34、 查询所有任课教师的tname和depart.
#方式1
SELECT tname,depart FROM teacher WHERE tname IN (SELECT DISTINCT tname FROM teacher,course,score WHERE teacher.tno=course.tno AND course.cno=score.cno)
#方式2
SELECT tname,depart FROM teacher WHERE tno IN (SELECT tno FROM course WHERE cno IN (SELECT DISTINCT cno FROM score))#35 、 查询所有未讲课的教师的tname和depart.
SELECT tname,depart FROM teacher WHERE tname NOT IN (SELECT DISTINCT tname FROM teacher,course,score WHERE teacher.tno=course.tno AND course.cno=score.cno)#36、查询至少有2名男生的班号。
SELECT class FROM student WHERE ssex='男' GROUP BY class HAVING COUNT(*)>1#37、查询student表中不姓“王”的同学记录。
SELECT * FROM student WHERE sname NOT LIKE ('王%')#38、查询student表中每个学生的姓名和年龄。
SELECT sname,YEAR(NOW())-YEAR(sbirthday) FROM student#39、查询student表中最大和最小的sbirthday日期值。
SELECT MAX(sbirthday) AS 最大,MIN(sbirthday) AS 最小 FROM student#40、以班号和年龄从大到小的顺序查询student表中的全部记录。
#查询student表中的全部记录。按照班号和年龄降序排序
SELECT * FROM student ORDER BY class DESC,sbirthday ASC#41、查询“男”教师及其所上的课程。
SELECT tname,cname FROM teacher,course WHERE tsex='男' AND teacher.tno=course.tno#42、查询最高分同学的sno、cno和degree列。
SELECT sno,cno,degree FROM score WHERE degree=(SELECT MAX(degree)FROM score)#43、查询和“李军”同性别的所有同学的sname.
SELECT sname FROM student WHERE ssex=(SELECT ssex FROM student WHERE sname='李军') AND sname NOT IN ('李军')#44、查询和“李军”同性别并同班的同学sname.
SELECT sname FROM student WHERE ssex=(SELECT ssex FROM student WHERE sname='李军') AND sname NOT IN ('李军') AND class=(SELECT class FROM student WHERE sname='李军')#45、查询所有选修“计算机导论”课程的“男”同学的成绩表。
SELECT sno,degree FROM score WHERE sno IN (SELECT sno FROM student WHERE ssex='男') AND cno IN (SELECT cno FROM course WHERE cname='计算机导论')
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