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概述

续一下之前讲的sql练习方面内容，怕有些朋友找不到数据，所以这里把建表和准备数据部分也放着。

建表语句

CREATE TABLE students
(sno VARCHAR(3) NOT NULL, 
sname VARCHAR(4) NOT NULL,
ssex VARCHAR(2) NOT NULL, 
sbirthday DATETIME,
class VARCHAR(5))

CREATE TABLE courses
(cno VARCHAR(5) NOT NULL, 
cname VARCHAR(10) NOT NULL, 
tno VARCHAR(10) NOT NULL)

CREATE TABLE scores 
(sno VARCHAR(3) NOT NULL, 
cno VARCHAR(5) NOT NULL, 
degree NUMERIC(10, 1) NOT NULL) 

CREATE TABLE teachers 
(tno VARCHAR(3) NOT NULL, 
tname VARCHAR(4) NOT NULL, tsex VARCHAR(2) NOT NULL, 
tbirthday DATETIME NOT NULL, prof VARCHAR(6), 
depart VARCHAR(10) NOT NULL)

插入数据

INSERT INTO STUDENTS (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (108 ,'曾华' ,'男' ,'1977-09-01',95033);
INSERT INTO STUDENTS (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (105 ,'匡明' ,'男' ,'1975-10-02',95031);
INSERT INTO STUDENTS (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (107 ,'王丽' ,'女' ,'1976-01-23',95033);
INSERT INTO STUDENTS (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (101 ,'李军' ,'男' ,'1976-02-20',95033);
INSERT INTO STUDENTS (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (109 ,'王芳' ,'女' ,'1975-02-10',95031);
INSERT INTO STUDENTS (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (103 ,'陆君' ,'男' ,'1974-06-03',95031);
INSERT INTO COURSES(CNO,CNAME,TNO)VALUES ('3-105' ,'计算机导论',825);
INSERT INTO COURSES(CNO,CNAME,TNO)VALUES ('3-245' ,'操作系统' ,804);
INSERT INTO COURSES(CNO,CNAME,TNO)VALUES ('6-166' ,'数据电路' ,856);
INSERT INTO COURSES(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' ,100);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (103,'3-245',86);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (105,'3-245',75);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (109,'3-245',68);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (103,'3-105',92);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (105,'3-105',88);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (109,'3-105',76);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (101,'3-105',64);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (107,'3-105',91);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (108,'3-105',78);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (101,'6-166',85);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (107,'6-106',79);
INSERT INTO SCORES(SNO,CNO,DEGREE)VALUES (108,'6-166',81);
INSERT INTO TEACHERS(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART) VALUES (804,'李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO TEACHERS(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART) VALUES (856,'张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO TEACHERS(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART) VALUES (825,'王萍','女','1972-05-05','助教','计算机系');
INSERT INTO TEACHERS(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART) VALUES (831,'刘冰','女','1977-08-14','助教','电子工程系');

题目（先思考如何实现）

1、查询所有学生的Sname、Cname和Degree列。

2、查询“95033”班所选课程的平均分。

3、假设使用如下命令建立了一个grade表：

create table grade(low number(3,0),upp number(3),rank char(1));

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;

现查询所有同学的Sno、Cno和rank列。

4、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。

5、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。

6、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。

7、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。

8、查询“张旭“教师任课的学生成绩。

9、查询选修某课程的同学人数多于5人的教师姓名。

10、查询95033班和95031班全体学生的记录。

11、查询存在有85分以上成绩的课程Cno.

12、查询出“计算机系“教师所教课程的成绩表。

13、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。

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。

15、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.

答案

1.查询所有学生的Sname、Cname和Degree列。

SELECT Sname,Cname,Degree
FROM Students INNER JOIN Scores
ON(Students.Sno=Scores.Sno) INNER JOIN Courses
ON(Scores.Cno=Courses.Cno)
ORDER BY Sname;

2.查询“95033”班所选课程的平均分。

SELECT Cname,AVG(Degree)
FROM Students INNER JOIN Scores
ON(Students.Sno=Scores.Sno) INNER JOIN Courses
ON(Scores.Cno=Courses.Cno)
WHERE Class='95033'
GROUP BY Courses.Cno
ORDER BY Cname;

3.假设使用如下命令建立了一个grade表：

CREATE TABLE grade(low TINYINT,upp TINYINT,rank CHAR(1));
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。

SELECT Sno,Cno,rank
FROM Scores INNER JOIN grade
ON(Scores.Degree>=grade.low AND Scores.Degree<=grade.upp)
ORDER BY Sno;

4.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 s1.Sno,s1.Degree
FROM Scores AS s1 INNER JOIN Scores AS s2
ON(s1.Cno=s2.Cno AND s1.Degree>s2.Degree)
WHERE s1.Cno='3-105' AND s2.Sno='109'
ORDER BY s1.Sno;

5.查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。

SELECT *
FROM Scores
GROUP BY Sno
HAVING COUNT(cno)>1 AND Degree!=MAX(Degree);

6.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 s1.Sno,s1.Degree
FROM Scores AS s1 INNER JOIN Scores AS s2
ON(s1.Cno=s2.Cno AND s1.Degree>s2.Degree)
WHERE s1.Cno='3-105' AND s2.Sno='109'
ORDER BY s1.Sno;

7.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 s1.Sno,s1.Sname,s1.Sbirthday
FROM Students AS s1 INNER JOIN Students AS s2
ON(YEAR(s1.Sbirthday)=YEAR(s2.Sbirthday))
WHERE s2.Sno='108';

8.查询“张旭“教师任课的学生成绩。

SELECT Sno,Degree
FROM Scores INNER JOIN Courses
ON(Scores.Cno=Courses.Cno) INNER JOIN Teachers
ON(Courses.Tno=Teachers.Tno)
WHERE Teachers.Tname='张旭';

9.查询选修某课程的同学人数多于5人的教师姓名。

SELECT DISTINCT Tname
FROM Scores INNER JOIN Courses
ON(Scores.Cno=Courses.Cno) INNER JOIN Teachers
ON(Courses.Tno=Teachers.Tno)
WHERE Courses.Cno IN(SELECT Cno FROM Scores GROUP BY(Cno) HAVING COUNT(Sno)>5);

10.查询95033班和95031班全体学生的记录。

SELECT *
FROM Students
WHERE Class IN ('95033','95031')
ORDER BY Class;

11.查询存在有85分以上成绩的课程Cno.

SELECT DISTINCT Cno FROM Scores WHERE Degree>85;

12.查询出“计算机系“教师所教课程的成绩表。

SELECT Tname,Cname,SName,Degree
FROM Teachers INNER JOIN Courses
ON(Teachers.Tno=Courses.Tno) INNER JOIN Scores
ON(Courses.Cno=Scores.Cno) INNER JOIN Students
ON(Scores.Sno=Students.Sno)
WHERE Teachers.Depart='计算机系'
ORDER BY Tname,Cname,Degree DESC;

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 Tname,Prof
FROM Teachers
WHERE Depart='计算机系' AND Prof NOT IN(
 SELECT DISTINCT Prof
 FROM Teachers
 WHERE Depart='电子工程系');

14.查询选修编号为“3-105“课程且成绩至少高于任意选修编号为“3-245”的同学的成绩的Cno、Sno和Degree,并按Degree从高到低次序排序。

SELECT Cno,Sno,Degree
FROM Scores
WHERE Cno='3-105' AND Degree > ANY(
 SELECT Degree
 FROM Scores
 WHERE Cno='3-245')
ORDER BY Degree DESC;

15.查询选修编号为“3-105”且成绩高于所有选修编号为“3-245”课程的同学的Cno、Sno和Degree.

SELECT Cno,Sno,Degree
FROM Scores
WHERE Cno='3-105' AND Degree > ALL(
 SELECT Degree
 FROM Scores
 WHERE Cno='3-245')
ORDER BY Degree DESC;