From 4d8ed92a8fbf7a846a44f51ae04ba67ad7074e4d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=94=90=E5=9B=BD=E4=BA=AE?= <647597435@qq.com> Date: Sun, 5 Mar 2023 11:14:25 +0800 Subject: [PATCH 1/2] =?UTF-8?q?20230305=E8=A1=A8=E6=A0=BC=E6=9F=A5?= =?UTF-8?q?=E8=AF=A2?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../20230305\344\275\234\344\270\232.md" | 131 ++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 "19\345\224\220\345\233\275\344\272\256/20230305\344\275\234\344\270\232.md" diff --git "a/19\345\224\220\345\233\275\344\272\256/20230305\344\275\234\344\270\232.md" "b/19\345\224\220\345\233\275\344\272\256/20230305\344\275\234\344\270\232.md" new file mode 100644 index 0000000..17d7022 --- /dev/null +++ "b/19\345\224\220\345\233\275\344\272\256/20230305\344\275\234\344\270\232.md" @@ -0,0 +1,131 @@ +# 作业 + +## 表格查询 + +```mysql +create database mxdx charset utf8; +use mxdx; +show databases ; +create database mxdx charset utf8; +use mxdx; +show tables; +create table Student( + Sno varchar(20) primary key , + Sname varchar(20) not null, + Ssex varchar(20), + Sbirthday datetime, + Class varchar(20) +); +select * from Student; +insert into student values + ('108','曾华','男','1997-9-1','95033'), + ('105','匡明','男','1975-10-2','95031'), + ('107','王丽','女','1976-1-23','95033'), + ('101','李军','男','1976-2-20','95033'), + ('109','王芳','女','1975-2-10','95031'), + ('103','陆君','男','1974-6-3','95031'); +CREATE TABLE `course` ( + `Cno` varchar(255) NOT NULL, + `Cname` varchar(255) NOT NULL, + `Tno` varchar(255) NOT NULL, + PRIMARY KEY (`Cno`), + KEY `Tno` (`Tno`), + CONSTRAINT `Tno` FOREIGN KEY (`Tno`) REFERENCES `teacher` (`Tno`) +) ENGINE=InnoDB DEFAULT CHARSET=utf8; +insert into Course values + ('3-105','计算机导论','825'), + ('3-245','操作系统','804'), + ('6-166','数字电路','856'), + ('9-888','高等数学','831'); +CREATE TABLE `score` ( + `Sno` varchar(20) NOT NULL, + `Cno` varchar(20) NOT NULL, + `Degree` decimal(4,1) DEFAULT NULL, + PRIMARY KEY (`Sno`,`Cno`), + KEY `Cno` (`Cno`), + CONSTRAINT `Cno` FOREIGN KEY (`Cno`) REFERENCES `course` (`Cno`), + CONSTRAINT `Sno` FOREIGN KEY (`Sno`) REFERENCES `student` (`Sno`) +) ENGINE=InnoDB DEFAULT CHARSET=utf8; +insert into Score values + ('103','3-245','86'), + ('105','3-245','75'), + ('109','3-245','68'), + ('103','3-105','92'), + ('105','3-105','88'), + ('109','3-105','76'), + ('101','3-105','64'), + ('107','3-105','91'), + ('108','3-105','78'), + ('101','6-166','85'), + ('107','6-166','79'), + ('108','6-166','81'); +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) +); +insert into Teacher values + ('804','李诚','男','1958-12-2','副教授','计算机系'), + ('856','张旭','男','1969-3-12','讲师','电子工程系'), + ('825','王萍','女','1972-5-5','助教','计算机系'), + ('831','刘冰','女','1977-8-14','助教','电子工程系'); +-- 4. 查询 +-- ①　查询Score表中的最高分的学生学号和课程号。 +select MAX(Degree) `Sno`, `Cno` from score; +-- ②　查询所有学生的Sname、Cno和Degree列。 +select Sname 姓名,Cno,Degree from student, score; +-- ③　查询所有学生的Sno、Cname和Degree列。 +select Sno,Cname,Degree from course,score; +-- ④　查询所有学生的Sname、Cname和Degree列。 +select Sname 姓名,Cname,Degree from course,score,student; +-- ⑤　查询“95033”班学生的平均分。 +select AVG(Degree) from student,score WHERE Class=95033; +-- ⑥　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 score where cno='3-105' and degree>76; +-- ⑦　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 max(degree) from score); +select Degree from score where Degree != (select max(degree) from score)group by Degree; +-- ⑧　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 s,score se where s.Sno=se.Sno and Degree> (select Degree from score where sno='109' and cno='3-105'); +-- ⑨　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。 +select year(Sbirthday) from student where sno='108'; +select sno ,Sname,Sbirthday from student where year(Sbirthday)=(select year(Sbirthday) from student where sno='108'); +-- ⑩　查询“张旭“教师任课的学生成绩。 +select * from teacher where Tname='张旭'; +select Degree from teacher t ,course c ,score s where t.Tno=c.Tno and c.Cno=s.cno and t.Tname='张旭'; +-- 11　查询选修某课程的同学人数多于5人的教师姓名。 +select s.Cno from teacher t ,course c ,score s where t.Tno=c.Tno and c.Cno=s.cno group by c.Cno having count(s.Cno)>5; +-- 12　查询出“计算机系“教师所教课程的成绩表。 +select tname ,prof from teacher where Depart='计算机系' +union +select tname ,prof from teacher where Depart='电子工程系'; +-- 13　查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。 +select Degree from score where Cno='3-245'; +select * from score where Cno='3-105' and Degree >= all (select Degree from score where Cno='3-245') order by Degree desc ; +-- 14　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 > all (select Degree from score where Cno='3-245'); +-- 16　查询成绩比该课程平均成绩低的同学的成绩表。 +select avg(Degree) from score; +select Degree from score where Degree< (select avg(Degree) from score); + +-- 17　查询所有任课教师的Tname和Depart. +select Tname,Depart from teacher; +-- 18　查询所有未讲课的教师的Tname和Depart. +select Tname,Depart from teacher left join Course C on Teacher.Tno = C.Tno left join score s on C.Cno = s.Cno where Sno is null ; + +-- 19　查询“男”教师及其所上的课程。 +select t.*,c.Cname from teacher t ,course c where t.tno= c.Tno and t.Tsex='男'; +-- 20　查询最高分同学的Sno、Cno和Degree列。 +select * from score where Degree=(select max(Degree) from score); +-- 21　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'); +-- 22　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 Class=(select Class from student where sname='李军'); + +-- 23　查询所有选修“计算机导论”课程的“男”同学的成绩表 +select Ssex,Cname,Degree from student s,course c,score se where s.Sno=se.Sno and se.Cno=c.Cno and Cname='计算机导论' and Ssex='男'; +``` + -- Gitee From c2e47f05629872d01146441604eaecca5c148efd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=94=90=E5=9B=BD=E4=BA=AE?= <647597435@qq.com> Date: Tue, 7 Mar 2023 21:52:14 +0800 Subject: [PATCH 2/2] =?UTF-8?q?20230307=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../20230307.md" | 149 ++++++++++++++++++ 1 file changed, 149 insertions(+) create mode 100644 "19\345\224\220\345\233\275\344\272\256/20230307.md" diff --git "a/19\345\224\220\345\233\275\344\272\256/20230307.md" "b/19\345\224\220\345\233\275\344\272\256/20230307.md" new file mode 100644 index 0000000..8254981 --- /dev/null +++ "b/19\345\224\220\345\233\275\344\272\256/20230307.md" @@ -0,0 +1,149 @@ +# 作业20230307 + +## 表格 + +在如图的数据表上完成以下题目 + +```mysql +CREATE DATABASE text charset utf8; +use text; +CREATE table stuinfo( +stuNO VARCHAR(10) primary key, +stuName VARCHAR(10), +stuSex VARCHAR(10), +stuAge VARCHAR(10), +stuAddress VARCHAR(20), +stuSeat INT +); +CREATE table stuExam( +examNo int primary key auto_increment, +stuNO VARCHAR(10), +writtenExam int, +labExam INT +); +CREATE table stuMarks( +examNo int primary key auto_increment, +stuID VARCHAR(10), +score INT +); +alter table stuExam add foreign key (stuNO) references stuinfo(stuNO); +alter table stuMarks add foreign key (examNo) references stuExam(examNo); + + +INSERT into stuinfo VALUES +('s2501','张秋利','男',20,'美国硅谷',1), +('s2502','李斯文','女',18,'湖北武汉',2), +('s2503','马文才','男',18,'湖南长沙',3), +('s2504','欧阳俊雄','女',21,'湖北武汉',4), +('s2505','梅超风','男',20,'湖北武汉',5), +('s2506','陈旋风','男',19,'美国硅谷',6); + +INSERT INTO stuExam VALUES +(1,'s2501',50,70), +(2,'s2502',60,65), +(3,'s2503',86,70), +(4,'s2504',40,80), +(5,'s2505',70,85), +(6,'s2506',85,90); + +INSERT into stuMarks VALUES +(1,'s2501',88), +(2,'s2501',92), +(3,'s2501',53), +(4,'s2502',60), +(5,'s2502',99), +(6,'s2503',82); +``` + +1.查询出年龄比班上平均年龄大的学生的信息 + +```mysql +SELECT * FROM stuinfo WHERE stuAge>(SELECT avg(stuAge) FROM stuinfo); +``` + +2.查询出每个学生的学号，姓名，性别和选修课程的最高分（stuMarks） + +```mysql +SELECT a.stuNO,a.stuName,a.stuSex,max(score) FROM stuinfo a left join stumarks b on a.stuNo=b.stuID group by stuNo; +``` + +3.查询出每个学生的学号，姓名，性别和考试平均分（stuExam） + +```mysql +select a.stuNO,a.stuName,a.stuSex,(b.writtenExam+b.labExam)/2 平均分 from stuinfo a left join stuexam b on a.stuNO=b.stuNO; +``` + +4.查询性别是男并且年龄大于等于20的学生的信息(用两种方法实现：普通查询和子查询) + +```mysql +select * from stuinfo where stuSex='男' and stuAge>=20; +``` + +5.查询出年龄比所有男生年龄都大的女生的信息 + +```mysql +select * from stuinfo where stuSex='女' and stuAge>(select max(stuAge) from stuinfo where stuSex='男'); +``` + +6.查询出所有选修课程都及格的学生的信息 （stuMarks） + +```mysql +select a.* from stuinfo a, (select stuID from stumarks group by stuID having min(score)>=60) b where a.stuNO=b.stuID; +``` + +7.查询出参加考试的学生的信息（用表连接，in二种方法做）（stuMarks） + +```mysql +select a.* from stuinfo a,(select stuID from stumarks group by stuID) b where a.stuNO=b.stuID; +``` + +8.查询出没有参加考试的学生的信息（用表连接，in二种方法做）（stuMarks） + +```mysql +select * from stuinfo where stuNO not in(select stuID from stumarks group by stuID); +``` + +9.将有一门成绩成绩大于90分的学生的基本信息查询出来（stuMarks） + +```mysql +select a.* from stuinfo a,(select stuID from stumarks group by stuID having max(score)>90) b where a.stuNO=b.stuID; +``` + +10.查询出平均成绩在80分以上的学生的基本信息（stuMarks） + +```mysql +select a.* from stuinfo a,(select stuID from stumarks group by stuID having avg(score)>80) b where a.stuNO=b.stuID; +``` + +11.查询出某同学所有考试成绩比“张秋利”同学所有分数都高的学生基本信息（stuMarks） + +```mysql +select a.* from +stuinfo a, +(select stuID from stumarks where stuID!='s2501' group by stuID having max(score)>(select max(score) from stumarks where stuID='s2501')) b +where + a.stuNO=b.stuID; +``` + +12.查询出某同学所有考试成绩只需要比“张秋利”同学某个分数高的学生基本信息（stuMarks） + +```mysql +select a.* from +stuinfo a, +(select stuID from stumarks where stuID!='s2501' group by stuID having max(score)>(select min(score) from stumarks where stuID='s2501')) b +where + a.stuNO=b.stuID; +``` + +13.查询班上比所有男生年龄都要大的女生的信息 + +```mysql +select * from stuinfo where stuSex='女' and stuAge>(select max(stuAge) from stuinfo where stuSex='男'); +``` + +14.查询出只是比某个男生年龄大的女生的信息 + +```mysql +select * from stuinfo where stuSex='女' and stuAge>(select min(stuAge) from stuinfo where stuSex='男'); +``` + -- Gitee