mysql日常基本语句

注：基于（https://blog.csdn.net/xiaosa_kun/article/details/84868547）所修改，修改查询语句的第16，27。

1.新建数据库

CREATE DATABASE school;

设有一个数据库school，包括四个表：学生表（student）、课程表（course）、成绩表（score）以及教师信息表（teacher）。用SQL语句创建四个表并完成相关题目。
创建学生表

CREATE TABLE student (sno varchar(20) NOT NULL PRIMARY KEY, sname varchar(20) NOT NULL, ssex varchar(20) NOT NULL, sbirthday datetime, class varchar(20)
) ENGINE = innodb CHARSET = utf8;

创建教师表

CREATE TABLE teacher (tno varchar(20) NOT NULL PRIMARY KEY, tname varchar(20) NOT NULL, tsex varchar(20) NOT NULL, tbirthday datetime, prof varchar(20), depart varchar(20) NOT NULL
) ENGINE = innodb CHARSET = utf8;

创建课程表

CREATE TABLE course (cno varchar(20) NOT NULL PRIMARY KEY, cname varchar(20) NOT NULL, tno varchar(20) NOT NULL, FOREIGN KEY (tno) REFERENCES teacher (tno)
) ENGINE = innodb CHARSET = utf8;

创建成绩表

CREATE TABLE score (sno varchar(20) NOT NULL, FOREIGN KEY (sno) REFERENCES student (sno), cno varchar(20) NOT NULL, FOREIGN KEY (cno) REFERENCES course (cno), degree decimal NOT NULL
) ENGINE = innodb CHARSET = utf8;

2.插入数据库

插入学生表数据

use student;
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);

插入教师表数据

use teacher;
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');

插入课程表数据

use course;
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' ,'数据电路' ,856);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' ,831);

插入成绩表数据

use score;
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,'9-888',79);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'6-166',81);

3.查询数据

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 depart
FROM teacher
GROUP BY depart;

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。(between)

SELECT *
FROM score
WHERE degree BETWEEN 60 AND 80;

5、查询Score表中成绩为85，86或88的记录。(in)

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。(排序)

SELECT sno, cno
FROM score
ORDER BY degree DESC;

11、查询每门课的平均成绩。(group by)

SELECT cname, AVG(degree)
FROM scoreINNER JOIN course
WHERE course.cno = score.cno
GROUP BY course.cname;

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。(group by having)

SELECT cno, AVG(degree)
FROM score
WHERE cno LIKE '3%'
GROUP BY cno
HAVING COUNT(sno) >= 5;

13、查询最低分大于70，最高分小于90的Sno列。

SELECT sno
FROM score
GROUP BY sno
HAVING MAX(degree) < 90
AND MIN(degree) > 70;

14、查询所有学生的Sname、Cno和Degree列。

SELECT sname, score.cno, degree
FROM studentINNER JOIN score
WHERE student.sno = score.sno;

15、查询所有学生的Sno、Cname和Degree列。

SELECT student.sno, sname, degree
FROM studentINNER JOIN score
WHERE student.sno = score.sno;

16、查询所有学生的Sname、Cname和Degree列。

select sname,cname,degree
from student
inner join score,course
where
course.cno = score.cno and student.sno = score.sno;

17、查询“95033”班学生的平均分。(选)

SELECT AVG(degree)
FROM studentINNER JOIN score
WHERE class = '95033'AND student.sno = score.sno;

18、假设使用如下命令建立了一个grade表,并查询所有同学的Sno、Cno和rank列。

create table grade(low int(3),high int(3),rank varchar(20));
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');
commit;

select sno,cno,rank
from score
inner join grade
where degree < high and degree >low;

19、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。(选)

SELECT *
FROM score
WHERE degree > (SELECT degreeFROM scoreWHERE sno = '109'AND cno = '3-105');

20、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。(选)

SELECT sno, sname, sbirthday
FROM student, (SELECT year(sbirthday) AS birthyearFROM studentWHERE sno = 108) s1
WHERE year(sbirthday) = s1.birthyear;

21、查询“张旭“教师任课的学生成绩。(选)

SELECT tname, cname, sname, degree
FROM teacher, course, student, score
WHERE teacher.tno = course.tnoAND course.cno = score.cnoAND score.sno = student.snoAND teacher.tname = '张旭';

22、查询95033班和95031班全体学生的记录。(in)

SELECT *
FROM student
WHERE class IN ('95033', '95031');

23、查询存在有85分以上成绩的课程cno.

SELECT cno
FROM score
GROUP BY cno
HAVING MAX(degree) >= 85;

24、查询出“计算机系“教师所教课程的成绩表。(选)

SELECT score.sno, sname, degree
FROM teacher, score, course, student
WHERE teacher.tno = course.tnoAND course.cno = score.cnoAND score.sno = student.snoAND teacher.depart = '计算机系';

25、查询成绩比该课程平均成绩低的同学的成绩表。(选)

SELECT s.sno, s.cno, s.degree
FROM score AS s, (SELECT cno, AVG(degree) AS avgdFROM scoreGROUP BY cno) avgs
WHERE s.cno = avgs.cnoAND s.degree < avgs.avgd;

26、查询所有任课教师的Tname和Depart.(选)

SELECT tname, depart
FROM teacher;

27、查询至少有2名男生的班号。(group by having)

SELECT class, COUNT(sname)
FROM student
GROUP BY class
HAVING COUNT(sname) >= 2;

28、查询Student表中不姓“王”的同学记录。(not like)

SELECT *
FROM student
WHERE sname NOT LIKE '王%';

29、查询Student表中每个学生的姓名和年龄。

SELECT sname, 2018 - year(sbirthday) AS age
FROM student;

30、查询Student表中最大和最小的Sbirthday日期值。

SELECT MAX(sbirthday), MIN(sbirthday)
FROM student;

31、以班号和年龄从大到小的顺序查询Student表中的全部记录。
下面两种SQL语句一样的效果，年龄大则出生日期小

SELECT *
FROM student
ORDER BY class DESC, sbirthday ASC;

SELECT *
FROM student
ORDER BY class DESC, sbirthday;

32、查询“男”教师及其所上的课程。

SELECT tname, cname
FROM teacher, course
WHERE teacher.tno = course.tnoAND tsex = '男';

33、查询每一门科目最高分同学的Sno、Cno和Degree列。(选)

SELECT sno, cno, MAX(degree)
FROM score
GROUP BY cno;