1 Create Table student
2 (
3 Sno char (9) Primary key ,
4 Sname char (20) Unique ,
5 Ssex char (2) ,
6 Sage smallint ,
7 Sdept char(20)
8
9 );
10
11 Create Table Course
12 (
13 Cno char (4) Primary key ,
14 Cname char (40) not Null ,
15 Cpno char (4) ,
16 Ccredit smallint
17 foreign key (Cpno) References Course(Cno)
18 );
19
20 Create Table SC
21 (
22 Sno char (9) ,
23 Cno char (4) ,
24 Grade smallint
25
26 Primary key ( Sno , Cno ) ,
27 Foreign key ( Sno ) References Student (Sno),
28 Foreign key ( Cno ) References Course (Cno)
29
30 );
31
32 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
33 values('201215121','李勇','男',20,'CS');
34 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
35 values('201215122','刘晨','女',19,'CS');
36 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
37 values('201215123','王敏','女',18,'MA');
38 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
39 values('201215125','张立','男',19,'IS');
40
41
42 Insert Into Course(Cno,Cname,Cpno,Ccredit)
43 values('2','数学',NULL,2)
44 Insert Into Course(Cno,Cname,Cpno,Ccredit)
45 values('6','数据处理',NULL,2)
46 Insert Into Course(Cno,Cname,Cpno,Ccredit)
47 values('4','操作系统','6',3)
48 Insert Into Course(Cno,Cname,Cpno,Ccredit)
49 values('7','PASCAL语言','6',4)
50 Insert Into Course(Cno,Cname,Cpno,Ccredit)
51 values('5','数据结构','7',4)
52 Insert Into Course(Cno,Cname,Cpno,Ccredit)
53 values('1','数据库','5',4)
54 Insert Into Course(Cno,Cname,Cpno,Ccredit)
55 values('3','信息系统','1',4)
56
57 /*
58 drop table SC;
59 drop table Course;
60 drop table student;
61 */
62
63
64 Insert Into SC(Sno,Cno,Grade)
65 values ( '201215121' , '1' , 92 )
66 Insert Into SC(Sno,Cno,Grade)
67 values ( '201215121' , '2' , 85 )
68 Insert Into SC(Sno,Cno,Grade)
69 values ( '201215121' , '3' , 88 )
70 Insert Into SC(Sno,Cno,Grade)
71 values ( '201215122' , '2' , 90 )
72 Insert Into SC(Sno,Cno,Grade)
73 values ( '201215122' , '3' , 80 )
1 Create Table student
2 (
3 Sno char (9) Primary key ,
4 Sname char (20) Unique ,
5 Ssex char (2) ,
6 Sage smallint ,
7 Sdept char(20)
8
9 );
10
11 Create Table Course
12 (
13 Cno char (4) Primary key ,
14 Cname char (40) not Null ,
15 Cpno char (4) ,
16 Ccredit smallint
17 foreign key (Cpno) References Course(Cno)
18 );
19
20 Create Table SC
21 (
22 Sno char (9) ,
23 Cno char (4) ,
24 Grade smallint
25
26 Primary key ( Sno , Cno ) ,
27 Foreign key ( Sno ) References Student (Sno),
28 Foreign key ( Cno ) References Course (Cno)
29
30 );
31
32 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
33 values('201215121','李勇','男',20,'CS');
34 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
35 values('201215122','刘晨','女',19,'CS');
36 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
37 values('201215123','王敏','女',18,'MA');
38 Insert Into student(Sno,Sname,Ssex,Sage,Sdept)
39 values('201215125','张立','男',19,'IS');
40
41
42 Insert Into Course(Cno,Cname,Cpno,Ccredit)
43 values('2','数学',NULL,2)
44 Insert Into Course(Cno,Cname,Cpno,Ccredit)
45 values('6','数据处理',NULL,2)
46 Insert Into Course(Cno,Cname,Cpno,Ccredit)
47 values('4','操作系统','6',3)
48 Insert Into Course(Cno,Cname,Cpno,Ccredit)
49 values('7','PASCAL语言','6',4)
50 Insert Into Course(Cno,Cname,Cpno,Ccredit)
51 values('5','数据结构','7',4)
52 Insert Into Course(Cno,Cname,Cpno,Ccredit)
53 values('1','数据库','5',4)
54 Insert Into Course(Cno,Cname,Cpno,Ccredit)
55 values('3','信息系统','1',4)
56
57 /*
58 drop table SC;
59 drop table Course;
60 drop table student;
61 */
62
63
64 Insert Into SC(Sno,Cno,Grade)
65 values ( '201215121' , '1' , 92 )
66 Insert Into SC(Sno,Cno,Grade)
67 values ( '201215121' , '2' , 85 )
68 Insert Into SC(Sno,Cno,Grade)
69 values ( '201215121' , '3' , 88 )
70 Insert Into SC(Sno,Cno,Grade)
71 values ( '201215122' , '2' , 90 )
72 Insert Into SC(Sno,Cno,Grade)
73 values ( '201215122' , '3' , 80 )
74
75
76 /*1、查询女生中年龄大于19岁的学生姓名*/
77 Select Sname
78 From student
79 where Sage>=19 and Ssex = '女';
80
81 /*2、查询计算机系的学生学号、姓名、出生年份，
82 按出生年份降序显示（给出生年份起个别名）；*/
83
84 Select Sno 学生学号 , Sname 姓名 , 2019 - Sage 出生年份
85 From student
86 Order by 2019 - Sage Desc;
87
88 /*3、查询没有先行课的课程号、课程名；*/
89
90 Select Cno 课程号 ,Cname 课程名
91 From Course
92 Where Cpno IS NULL;
93
94 /*4、查询选修了课程的学生学号；*/
95
96 Select distinct Sno 学生学号
97 From SC;
98
99 /*5、查询年龄在18到20岁之间的学生学号、姓名、性别；*/
100 Select Sno 学生学号, Sname 姓名 , Ssex 性别
101 From student
102 Where Sage between 18 and 23;
103
104 /*6、查询是计算机系或数学系的学生姓名，年龄；*/
105 Select Sname 学生姓名 , Sage 年龄
106 From student
107 Where Sdept in ('CS','MA');
108
109 /*7、查询课程名含有‘系统’的全部信息；*/
110 Select Cno 课程号 , Cname 课程名称 , Cpno 先行课号 , Ccredit 学分
111 From Course
112 Where Cname Like '%系统%';
113
114 /*8、查询学号倒数第二位是‘2’的学生姓名、院系；*/
115 Select Sno 学号 , Sname 学生姓名 , Sdept 院系
116 From student
117 Where Sno Like '%2_' ;
118
119 /*9、查询被选修了的课程号；*/
120 Select distinct Cno 已选修的课程号
121 From SC ;
122
123 /*10、查询学分大于3的课程号和课程名；*/
124 Select Cno 课程号 , Cname 课程名 , Ccredit 学分
125 From Course
126 Where Ccredit > 3 ;
1 //按照数据库 （1号课）从高到低 排序 2 3 select grade * 4 from SC 5 where Cno = '1' 6 order by grade Desc ; 7 8 //把所有课的成绩从高到低排序 9 select grade * 10 from SC 11 where grade is not NULL 12 order by grade Desc ; 13 14 //统计每门课的可好，及其最高成绩 15 select Cno , max( grade ) 16 from SC 17 group by Cno ; 18 19 //按照每个人的总成绩降序 20 select Sno , sum(grade) 21 from SC 22 where grade is not NULL 23 group by Sno 24 order by sum(grade) Desc ;
1 1、统计每个同学超过80分的课程的数目超过5门，输出对应的学号及课程号。 2 3 方法1: 4 5 Select Sno , Cno 6 from SC 7 Group by Sno having count( grade > 80 ) > 5 ; 8 9 方法2: 10 Select Sno , Cno 11 from SC 12 where grade > 80 13 group by Sno having Count(Cno) > 5; 14 15 16 2、间接先行课 17 Select A.Cno 课程号, B.Cpno 间接先行课 18 from course A , course B 19 where A.cpno = B.Cno; 20 21 3、查询与“刘晨”同学是同一个学院的学生 ,输出对应的学号，姓名，性别 22 Select B.Sno , B.Sname , B.Ssex 23 from student A , student B 24 where A.Sname = '刘晨' and A.Sdept = B.Sdept
1 嵌套查询 2 1、查询和“刘晨”同学同一个专业的学生，输出Sno,Sname 3 Select Sno, Sname 4 from student 5 where Sdept in( 6 7 select Sdept 8 from student 9 where Sname = '***' 10 ); 11 12 2、查询有间接先行课的课程号 13 Select Cno 14 from Course 15 where Cpno in( 16 17 select Cno 18 from Course 19 where Cpno is Not Null 20 ); 21 22 3、查询"数据库" 高于平均分的 学生->学号 23 24 Select Sno 25 from SC 26 where grade > 27 ( 28 select AVG(grade) 29 from SC 30 where Cno in ( 31 select Cno 32 from Course 33 where Cname = '数据库' 34 ) 35 ) and Cno in ( 36 select Cno 37 from Course 38 where Cname = '数据库' 39 ); 40 41 方法2: 42 select Sno 43 from SC,course 44 where Sc.cno = course.Cno and Cname = '数据库' 45 and grade > 46 ( 47 select AVG(grade) 48 from Sc , Course 49 where Sc.cno = course.Cno and Cname = '数据库' 50 )
1 实验名称：实验三：数据库连接查询和聚集函数 2 实验类型：设计型 3 4 实验要求和目的： 5 1、熟练掌握聚集函数 6 2、掌握连接查询的使用 7 8 9 实验步骤： 10 一、初始化数据库，还原三个表及数据； 11 二、实现以下查询： 12 1、查询每个学生的平均成绩；（输出学号、平均成绩） 13 2、查询每个学生的平均成绩；（输出学号、姓名、平均成绩） 14 3、查询数据库课程的最高分； 15 4、查询选修了1号课或3号课的学生姓名； 16 5、查询每个学院的学生人数； 17 6、查询计算机系的女生所有信息； 18 7、查询跟刘晨一个院系的学生学号、姓名； 19 8、查询选修人数超过2个人的课程号、课程名； 20 9、查询男女生人数； 21 10、按总成绩降序显示学生的学号、姓名、总成绩； 22 23 /*1、查询每个学生的平均成绩；（输出学号、平均成绩）*/ 24 Select Sno 学号 , AVG(grade)平时成绩 25 From SC 26 group by Sno ; 27 28 /*2、查询每个学生的平均成绩；（输出学号、姓名、平均成绩）*/ 29 Select student.Sno 学号 , Sname 姓名 , AVG(grade) 平时成绩 30 From student , SC 31 where student.Sno = SC.Sno 32 group by student.Sno , Sname ; 33 34 /*3、查询'数据库课程'的最高分；*/ 35 Select Course.Cname , MAX(Grade)最高分 36 From SC,Course 37 Where Course.Cno = Course.Cno And Course.Cname = '数据库' 38 Group by Cname ; 39 40 /*4、查询选修了1号课或3号课的学生姓名；*/ 41 Select distinct Sname 姓名 42 from student , SC 43 where SC.Sno = student.Sno and (SC.Cno = 1 or SC.Cno = 3) ; 44 45 /*5、查询每个学院的学生人数；*/ 46 Select Sdept 学院,COUNT(*) 学生人数 47 from student 48 group by Sdept ; 49 50 /*6、查询计算机系的女生所有信息；*/ 51 Select Sno 学号 , Sname 姓名 , Ssex 性别 , Sage 年龄 , Sdept 学院 52 from student 53 where Ssex = '女' and Sdept = 'CS'; 54 55 /*7、查询跟刘晨一个院系的学生学号、姓名；*/ 56 Select A.Sno 学生学号 , A.Sname 姓名 57 from student A , student B 58 where B.Sdept = A.Sdept and B.Sname = '刘晨' ; 59 60 /*8、查询选修人数超过2个人的课程号、课程名；*/ 61 Select SC.Cno 课程号 , Cname 课程名 62 from SC , Course 63 where SC.Cno = Course.Cno 64 group by SC.Cno , Cname having COUNT(Sno) >= 2 ; 65 66 67 /*9、查询男女生人数；*/ 68 Select Ssex 性别, COUNT(Sno) 人数 69 from student 70 group by Ssex ; 71 72 /*10、按总成绩降序显示学生的学号、姓名、总成绩；*/ 73 Select stu.Sno 学号 , Sname 姓名 , SUM(Grade) 总成绩 74 from student stu , SC 75 where stu.Sno = SC.Sno 76 group by stu.Sno , Sname 77 order by SUM(Grade) DESC ;
1 1、利用嵌套查询：与刘晨同专业的姓名和学号 2 3 select Sno,Sname 4 from Student 5 where Sdept in( 6 Select Sdept 7 From Student 8 where Sname = '刘晨' 9 ) 10 11 2、查询选修了课程名为“信息系统”的学生学号，姓名 12 13 Select Sno , Sname 14 From Student 15 Where Sno in ( 16 Select Sno 17 from Sc 18 where Cno in ( 19 Select Cno 20 From Course 21 where Cname = '信息工程' 22 ) 23 ) 24 25 26 3、查询比自身平均分高的那门课 27 Select Cno 28 From Sc X 29 where Grade > ( 30 select AVG(grade) 31 from Sc Y 32 where Y.Sno = X.Sno 33 ) 34 35 4、查询除CS外的专业的学生，比CS中任意一个年纪大的学号和姓名。 36 Select Sno , Sname 37 from Student 38 where age < ANY( 39 Select Sage 40 from Student 41 where Sdept = 'CS' 42 )and Sdept <> 'CS' 43 44 5、查询选修了全部课程的学生姓名 45 46 Select Sname 47 from Student 48 Where NOT EXIST ( 49 Select * (Cno) 50 from Course 51 where NOT EXIST( 52 Select * 53 From Sc 54 where Sc.Cno = Course.Cno and Sc.Sno = Student.Sno 55 ) 56 )
1 /*1、查询选修了1号课的学生姓名（用2种方法实现）*/ 2 3 /* 方法1 - 嵌套查询*/ 4 Select Sname 学生姓名 5 From student 6 where Sno in ( 7 Select Sno 8 From SC 9 where Cno = '1' 10 ); 11 12 /* 方法2 - 外部连接*/ 13 Select Sname 学生姓名 14 From SC , student 15 where SC.Sno = student.Sno and SC.Cno = '1' ; 16 17 /* 方法3 - Exists*/ 18 Select Sname 学生姓名 19 From student 20 where Exists( 21 select * 22 From SC 23 where Cno = '1' and student.Sno = SC.Sno 24 ); 25 26 /* 2、查询没有选修1号课的学生学生姓名 */ 27 28 /* 利用NOT in 语句*/ 29 Select Sname 学生姓名 30 From student 31 where Sno Not in( 32 select Sno 33 from SC 34 where student.Sno = SC.Sno and SC.Cno = '1' 35 ); 36 37 /* 利用NOT EXISTS语句*/ 38 Select Sname 学生姓名 39 From student 40 where NOT EXISTS( 41 select * 42 From SC 43 where student.Sno = SC.Sno and SC.Cno = '1' 44 ); 45 46 47 /*3、查询没有选修数据库的学生姓名*/ 48 Select Sname 学生姓名 49 From student 50 where EXISTS( 51 Select * 52 from Course 53 where Cname = '数据库' and NOT EXISTS( 54 Select * 55 From SC 56 where student.Sno = SC.Sno and Course.Cno = SC.Cno 57 ) 58 ); 59 60 /*4、查询计算机学院男生中比该学院所有女生年龄都大的学号、姓名、年龄；*/ 61 Select Sno 学号 , Sname 姓名 , Sage 年龄 62 from student A 63 where A.Ssex = '男' 64 and A.Sage > ALL( 65 Select Sage 66 From student B 67 where B.Ssex = '女' and A.Sdept = B.Sdept 68 ) 69 and A.Sdept = 'CS' 70 ; 71 72 /*5、查询比自己平均成绩低的学生学号、课程号、课程名；*/ 73 Select Sno 学生学号 , X.Cno , Course.Cname 74 From SC X, course 75 where X.Cno = Course.Cno and Grade < ( 76 Select AVG(Grade) 77 From SC Y 78 where Y.Sno = X.Sno 79 ); 80 81 /*6、查询每个学生的选课情况；（输出学号、姓名、课程号、成绩）在kingbase 里实现；*/ 82 Select stu.Sno 学号 , Sname 姓名 , Cno 课程号 , Grade 成绩 83 From student stu, SC 84 where stu.Sno = SC.Sno ; 85 86 /*7、查询选修了1号课和3号课的学生姓名；*/ 87 88 /*方法1 ：利用两次查询取交集*/ 89 Select Sname 学生姓名 90 from student 91 where Sno in ( 92 Select Sno 93 From SC 94 where SC.Sno = student.Sno and Cno = '1' 95 ) and Sno in ( 96 Select Sno 97 From SC 98 where SC.Sno = student.Sno and Cno = '3' 99 ); 100 101 /*方法2 ：直接利用Union语句*/ 102 Select Sname 学生姓名 103 from student 104 where Sno in( 105 106 Select Sno 107 from SC 108 where Cno = '1' 109 110 intersect 111 112 Select Sno 113 from SC 114 where Cno = '3' 115 ); 116 117 118 /*---------------------------------*/ 119 120 /*1、将数据库课程的学分改为5；*/ 121 /*注释 ：未修改前为 ：4学分*/ 122 Update Course 123 Set Ccredit = 5 124 where Cname = '数据库'; 125 126 /*2、删除刘晨的所有信息；*/ 127 Delete 128 From SC 129 where Sno in( 130 Select Sno 131 From student 132 where SC.Sno = student.Sno and Sname = '刘晨' 133 ); 134 135 Delete 136 From student 137 where Sname = '刘晨'
1 1、查询每个学生的选课数量 2 3 Select Sno , Count(Cno) 4 from Sc 5 Group by Sno 6 having Count(*) = 5 ; 7 8 2、查询选了所有的课程的 学生 9 10 Select Sname 11 from Student 12 Where Sno in( 13 Select Sno 14 From Sc 15 Group by Sno 16 Having count(*) = ( 17 Select count(*) 18 from course 19 ) 20 ) 21 22 3、查询至少选修了学生2015122选修的全部课程的学生学号 23 方法1: 24 25 Select distinct Sno 26 From Sc Scx 27 where Not exists( 28 Select * 29 from Sc Scy 30 where Scy.Sno = '2015122' and 31 not exists( 32 select * 33 from Sc Scz 34 where Scz.Sno = Scx.Sno and 35 Scz.Cno = Scy.Sno) 36 ) 37 ); 38 39 方法2: 40 Select Distinct Sno 41 from Sc 42 where Cno in( 43 Select Cno 44 from Sc 45 where Sno = '2015122' 46 ) 47 Group by Sno 48 Having count(*) = ( 49 Select count(*) 50 from Sc 51 where Sno = '2015122' 52 ); 53 54 10-16 课堂讲解事例
1 1、查询 每门课都及格 的学生的学号 2 3 Select distinct Sno 4 from Sc A 5 where Not exists( 6 Select * 7 from Sc B 8 where A.Sno = B.Sno and B.Grade < 60 9 ); 10 11 2、查询 既有 “课程大于90分” 又有“课程不及格” 的学生的学号 12 Select distinct A.Sno 13 from Sc A 14 where exists( 15 Select * 16 from Sc B 17 where A.Sno = B.Sno and Grade > 90 18 ) and exists ( 19 Select * 20 from Sc C 21 where A.Sno = C.Sno and Grade < 60 22 ) 23 Group by Sno 24 25 26 3、查询 "平均分不及格的课程号" 和 "平均成绩" 27 28 select Cno , AVG(Grade) 29 from Sc 30 Group by Cno 31 having AVG(Grade) < 60 32 33 34 35 4、找出至少选修了２号学生选修过的全部课程的学生号 36 Select Sno 37 from Sc 38 where Cno in( 39 Select Cno 40 from Sc 41 where Sno = '201215122' 42 ) 43 Group by Sno 44 Having count(*) = ( 45 Select count(*) 46 from Sc 47 where Sno = '201215122' 48 ); 49 50 5、查询7号课程没有考试成绩的学生学号 51 52 Select Sno 53 from Sc 54 where Cno = '7' and Grade is NULL 55 56 57 6、查询7号课程成绩在90分以上或60分以下的学生学号 58 59 Select Sno 60 from Sc 61 where Cno = '7' and ( Grade < 60 or Grade > 90 ) 62 63 64 65 7、查询课程名以"数据"两个字开头的所有课程的课程号和课程名 66 67 Select Cno , Cname 68 from Course 69 where Cname like '数据%' 70 71 72 8、查询每个学生所有课程的平均成绩,输出学生学号和平均成绩 73 74 Select Sno , AVG(Grade) 75 from Sc 76 group by Sno 77 78 79 9、查询选修7号课的学生的学号、姓名、性别 80 Select A.Sno 学号 , A.Sname 姓名 , A.Ssex 性别 81 from student A , Sc B 82 where A.Sno = B.Sno and B.Cno = '2' 83 84 85 86 10、查询有30名以上的学生选修的课程号 87 Select Cno 88 from Sc 89 Group by Cno 90 Having count(*) >= 30 ; 91 92 11、查询至今没有考试考试不及格的学生学号 93 94 Select Sno 95 from Sc A 96 where Not exists( 97 Select * 98 from Sc B 99 where B.Sno = A.Sno and ( B.Grade is NULL or B.Grade < 60 ) 100 ) 101 group by Sno 102 103 104 105 12、查询没有选修1号课的学生 输出其姓名(用3种方法实现) 106 107 方法1: 108 Select distinct A.Sno 109 from Sc A 110 where ( Select Cno 111 from Sc B 112 where A.Sno = B.Sno and B.Cno = '1' ) is NULL 113 114 方法2: 115 Select Sno 116 from Student 117 Except 118 Select Sno 119 from Sc 120 where Cno = '1' 121 122 123 方法3: 124 Select distinct Sno , Sname 125 from Student 126 where not exists ( 127 select * 128 from Sc 129 where Cno = '1' and student.Sno = Sc.Sno 130 ) 131 132 13、查询至少选修了刘晨选的全部课程的学生学号 133 Select Sno 134 from Sc 135 where Cno in ( 136 Select Cno 137 from Sc , Student 138 where student.Sno = Sc.sno and Sname ='刘晨' 139 ) 140 Group by Sno 141 having count(*) = ( 142 Select count(*) 143 from Sc , Student 144 where student.Sno = Sc.sno and Sname ='刘晨' 145 ) 146 147 14、查询每个学院学生的平均年龄,并把结果插入到一个新表Sdep_Avg(Sdep,age); 148 149 Create table Dept_age( 150 Sdept char(20) , 151 Avg_age smallint 152 ); 153 154 Insert into 155 dept_age( Sdept , Avg_age ) 156 Select Sdept , AVG( Sage ) 157 from Student 158 group by Sdept ; 159 160 15、将"刘晨"的信息系统课程成绩改为90分 161 162 Update SC 163 Set Grade = 90 164 where Sno in ( 165 Select Sc.Sno 166 from Student , Sc 167 where Student.Sno = Sc.Sno and Student.Sname = '刘晨' 168 )
1 查询选修了1号课 "或" 2号课的学生学号 2 3 Select Sno 4 From Sc 5 where Cno = '1' 6 UNION 7 Select Sno 8 From Sc 9 where Cno = '2' 10 11 查询选修了1号课 "和" 2号课的学生学号 12 Select Sno 13 from Sc 14 where Cno = '1' 15 Intersect 16 select Sno 17 from Sc 18 where Cno = '2' 19 20 21 查询没有选修1号课的学生学号 22 方法1: 23 Select distinct A.Sno 24 from Sc A 25 where( 26 select Cno 27 from Sc B 28 where A.Sno = B.Sno and B.Cno = '1' 29 ) is NULL 30 31 方法2: 32 Select Sno 33 from Sc 34 Except 35 Select Sno 36 from Sc 37 where Cno = '1' 38 39 方法3: 40 Select distinct Sno 41 from Sc 42 where Cno = '1' And 43 Group by Sno 44 Having count(*) = 0 45 46 方法4: 47 Select distinct Sno 48 from Sc A 49 where Not exist( 50 Select * 51 from Sc B 52 where A.Sno = B.Sno and B.Cno = '1' 53 )
1 Create table student
2 (
3 Sno char(9) ,
4 Constraint StdentKey primary key(Sno) ,
5 Sname char(20)
6 Constraint C1 Not Null ,
7 Ssex char(2)
8 Constraint C2 Check( Ssex in('男','女') ) ,
9 Sage Smallint
10 Constraint C3 Check( 15 <= Sage AND Sage <= 35 ),
11 Sdept char(20)
12 Constraint C4 Not Null
13 );
14
15 Create table Course(
16 Cno Char(9) ,
17
18 Cname Char(9)
19 Constraint C1 Unique ,
20
21 Cpno Char(9) ,
22
23 Constraint CourseForKey foreign key ( Cpno )
24 References Cno( Cpno ) ,
25
26 Ccredit Smallint
27 Constraint C2 Not Null ,
28
29 Constraint CourseKey primary key ( Cno )
30 );
31
32 Create table SC (
33 Sno Char(9) ,
34 Cno Char(9) ,
35 Grade Smallint
36 Constraint C1 Check( 0 <= Grade and Grade <= 100 ) ,
37 Constraint SCKey1 primary key ( Sno , Cno )
38 );
39
40 Alter table Student
41 Drop Constraint C3 ;
42 Alter table Student
43 Add Constraint C3 Check( 15 <= Sage and Sage <= 50 )
44
45
46 Create table s_count(
47 Ssex Char(9),
48 Scount Smallint
49 );
50
51
52 Insert Into S_count
53 values( ‘男’ , 0 )
54
55 Insert Into S_count
56 values( ‘女’ , 0 )
57
58 Create trigger count_student
59 After Insert On Student
60 for each Row
61 Begin
62 if (new.Ssex = ‘男’)
63 Update S_count
64 Set Scount = Scount + 1
65 where Ssex = ‘男’
66 end if
67
68 if (new.Ssex = ‘女’ )
69 Update S_count
70 Set Scount = Scount + 1
71 where Ssex = ‘女’
end if
72 End;
73
74 Update S_count
75 set Scount = 0 ;
76
77 Delete
78 from Student ;
79
80
81 Insert Into
82 Student
83 values( '20172899' ,'hhz','男',18,'CS');
84
85 Insert Into
86 Student
87 values( '20172900' ,'haz','女',18,'CS');
88
89 Insert Into
90 Student
91 values( '20172901' ,'wb','男',22,'CS');
1 1、新建用户u1、u2，u3 （connect类型） 2 2、将对student、course、sc三个表的查询、增删改权限授予u1,同时u1具有继续授予其他用户的权利； 3 4 grant select , update , delete 5 on table student , course , Sc 6 to u1 7 with grant option 8 9 3、以u1身份登录，将对三个表的查询权利授给u2； 10 11 grant select 12 on table student , courst , Sc 13 to u2 14 15 16 4、以u1身份登录，将对三个表的查询，增加、修改的权利授给u3； 17 18 grant select,update,delete 19 on table student , courst , Sc 20 to u3 21 22 5、回收u1的对三个表的增删改权利 23 24 revoke select, update , delete 25 on table student , course , Sc 26 from u1
1 P71页习题 2 1、求供应工程J1零件的供应商号码Sno 3 4 Select dinstinct Sno from SPJ 5 where jno = 'J1'; 6 7 2、求供应工程J1零件P1的供应商号码Sno 8 9 Select Sno from SPJ 10 where Jno = 'J1' and Pno = 'p1'; 11 12 3、求供应工程J1零件为红色的供应商号码Sno 13 Select Sno 14 from P , SPJ 15 where SPJ.Pno = P.pno AND jno = 'J1' AND color = '红' 16 17 4、求没有使用天津供应商生产的红色零件的工程号Jno 18 19 Select jno from J 20 Except 21 Select jno from SPJ , P , S 22 where 23 SPJ.pno = P.pno 24 AND SPJ.Sno = S.Sno 25 AND city = '天津' 26 AND color = '红' 27 28 5、求至少用了供应商S1所供应的全部零件的工程号Jno 29 Select distinct jno 30 from SPJ A 31 where not exists( 32 Select * 33 From SPJ B 34 where Sno = 'S1' AND 35 not exists( 36 Select * 37 from SPJ C 38 where C.Jno = A.Jno 39 AND C.Sno = 'S1' AND C.pno = B.pno 40 ) 41 )
11 - 1 课堂讲解事例
1、查询没有选修过课的学号
2、查询没有不及格的学生学号
3、查询没有选过课的学生 输出其 学号 、姓名
4、查询选择1号课 或者 2号课的学生学号
5、查询选择1号课 和 2号课的学生学号
6、查询选修了全部课程的学生号码和姓名
11月6号 课堂讲解事例
1、求供应工程J1零件的供应商号码Sno；
2、求供应工程J1零件P1的供应商号码Sno；
3、求供应工程J1零件为红色的供应商号码Sno；
4、求没有使用天津供应商生产的红色零件的工程号Jno；
5、求至少用了供应商S1所供应的全部零件的工程号Jno；
或者
设有关系数据库(S,SC,C),其中
S = ( S# 学号, Sn 姓名, Sa 年龄, Sex 性别)
Sc = ( S# 学号, C# 课号 , Cn 课程名)
C = C( C# 课程号 , Cn 课程名 , Tn 任课教师名字)
(1).查询LI老师所授课课程的课程号和课程名称
(2).查询年龄大于23岁的男学生学号和课程号
(3).查询WANG学生没选修的课程号
(4).查询至少选修了两门课程的学生学号
(5).查询全部学生都选修的课程的课程号和课程名称
S(Sno 学号,Sname 学生姓名, age 年龄, sex 性别)
C(Cno 课程号, Cname 课程名, Pcno 先行课号)
T(Tno 教师号, Tname 教师名, dep 专业)
Sc(Sno 学号, Cno 课程号, Tno 教师号, grade 成绩)
(1).求选修所有课程并且成绩为A的学生姓名
(2).求选修了王平老师教的所有课程的学生名
(3).求不选修信息系老师开设的课程的学生名
来源：https://www.cnblogs.com/Osea/p/11559919.html