mysql数据库练习题

来源：互联网发布：我是歌手有网络直播吗编辑：程序博客网时间：2024/05/16 00:40

有一段时间想好好的练习一下数据库就去网上找了好多练习题目。但是这些练习题目都感觉好少所以我把我搞到的所有数据库练习题综合了一下起来。喜欢的小好伙伴们赶紧收藏好了撒。一次够你练习几个小时了别坚持不下去了撒那我就贴出来了

//登录和退出数据库
1：mysql -u root -p//输入密码
2: exit
3: mysql -u root -p

create table if not exists student
(
SNO varchar(20) primary key,
SNAME varchar(20) character set gbk,
AGE int,
SEX char(2) character set gbk CHECK(SEX IN('男','女'))
);
insert into student values('1','李强',23,'男');
insert into student values('2','刘丽',22,'女');
insert into student values('5','张友',22,'男');

create table if not exists course
(
CNO varchar(20) primary key,
CNAME varchar(20) character set gbk,
TEACHER varchar(20) character set gbk
);
insert into course values('K1','C语言','王华');
insert into course values('K5','数据库原理','程军');
insert into course values('K8','编译原理','程军');

create table if not exists sc
(
SNO varchar(20) NOT NULL,
CNO varchar(20) NOT NULL,
SCORE int NOT NULL,
primary key (SNO,CNO),
foreign key (SNO) references student(SNO),
foreign key (CNO) references course(CNO)
);
insert into sc values('1','K1',83);
insert into sc values('2','K1',85);
insert into sc values('5','K1',92);
insert into sc values('2','K5',90);
insert into sc values('5','K5',84);
insert into sc values('5','K8',80);

select sname from student
where not exists
(
select * from course
where teacher='程军' and not exists
(
select * from sc
where sc.sno=student.sno and sc.cno=course.cno
)
);

select course.cno from course
where course.cno not in
(
select sc.cno from sc,student
where student.sname='李强' and student.sno=sc.sno
);

SELECT sc.sno
FROM sc
GROUP BY sc.sno HAVING count(*)>=3
;

SELECT sname FROM student
WHERE NOT EXISTS
(
SELECT * FROM course
WHERE NOT EXISTS
(
SELECT * FROM sc
WHERE course.cno=sc.cno and student.sno=sc.sno
)
);

SELECT * FROM student
WHERE sno not in
(
SELECT sc.sno FROM sc,course
WHERE course.cno=sc.cno
);

SELECT * FROM course
WHERE teacher='程军';

SELECT score FROM student,sc
WHERE student.sname='李强' AND student.sno=sc.sno
（3）查询课程名为“C语言”的平均成绩；
[sql] view plain copy
SELECT AVG(score) FROM sc,course
WHERE course.cname='C语言' AND course.cno=sc.cno
（4）查询选修了所有课程的同学信息。
[sql] view plain copy
SELECT * FROM student
WHERE NOT EXISTS
(
SELECT * FROM course
WHERE NOT EXISTS
(
SELECT * FROM sc
WHERE course.cno=sc.cno AND student.sno=sc.sno
)
);

SELECT cno,cname FROM course WHERE teacher LIKE '王%';

（2）检索年龄大于23岁的男学生的学号和姓名。
[sql] view plain copy
SELECT sno,sname FROM student
WHERE age>23;

（3）检索至少选修王老师所授课程中一门课程的女学生姓名。
[sql] view plain copy
SELECT sname FROM student
WHERE sex='女' AND sno IN
(
SELECT distinct sno FROM sc,course
WHERE teacher LIKE '王%' AND sc.cno=course.cno
);
（4）检索李同学不学的课程的课程号。
[sql] view plain copy
SELECT course.cno FROM course
WHERE course.cno NOT IN
(
SELECT sc.cno FROM sc,student
WHERE student.sname LIKE '李%' AND sc.sno=student.sno
);
（5）检索至少选修两门课程的学生学号。
[sql] view plain copy
SELECT sno FROM sc
GROUP BY sno HAVING (count(*)>=2);
（6）检索全部学生都选修的课程的课程号与课程名。
[sql] view plain copy
SELECT course.cno,course.cname FROM course
WHERE course.cno IN
(
SELECT cno FROM sc
GROUP BY cno HAVing count(*)=(SELECT count(*) FROM student)
);
（7）检索选修课程包含王老师所授课的学生学号。
[sql] view plain copy
SELECT DISTINCT sno FROM sc
WHERE cno IN
(
SELECT cno FROM course
WHERE teacher LIKE '王%'
);
（8）统计有学生选修的课程门数。
[sql] view plain copy
SELECT count(*) NumberOfCourse
FROM
(
SELECT DISTINCT cno FROM sc
GROUP BY cno
) AS testTab;
（9）求选修K1课程的学生的平均年龄。
[sql] view plain copy
SELECT AVG(age) AverageOfAge
FROM student
WHERE sno IN
(
SELECT sno FROM sc
WHERE cno='K1'
);
（10）求王老师所授课程的每门课程的学生平均成绩。
[sql] view plain copy
SELECT sc.cno,AVG(sc.score)
FROM sc
WHERE sc.cno IN
(
SELECT course.cno FROM course
WHERE course.teacher LIKE '王%'
)
GROUP BY sc.cno
（11）统计每门课程的学生选修人数（超过2人的课程才统计）。要求输出课程号和选修人数，查询结果按人数降序排列，若人数相同，按课程号升序排列。
[sql] view plain copy
SELECT cno,Num
FROM
(
SELECT cno,count(*) as Num
FROM sc
GROUP BY cno HAVING (count(*) >= 2)
) tb_temp
ORDER BY Num DESC,cno ASC
;
（12）检索学号比李同学大，而年龄比他小的学生姓名。
[sql] view plain copy
SELECT stu1.sname
FROM student stu1,
(
SELECT max(sno) snoLi,min(age) ageLi FROM student
WHERE sname LIKE '李%'
) AS stuLi
WHERE (stu1.age < stuLi.ageLi) AND (stu1.sno>stuLi.snoLi)
;
（13）检索姓名以李打头的所有学生的姓名和年龄。
[sql] view plain copy
SELECT sname,age FROM student
WHERE sname LIKE '李%'
;
（14）在SC中检索成绩为空值的学生学号和课程号。
[sql] view plain copy
SELECT sno,cno FROM sc
WHERE score IS NULL;
（15）求年龄大于女同学平均年龄的男学生姓名和年龄。
[sql] view plain copy
SELECT sname,age FROM student
WHERE
sex='男' AND age > (
SELECT AVG(age)
FROM student
WHERE sex='女'
)
;
（16）求年龄大于所有女同学年龄的男学生姓名和年龄。

[sql] view plain copy
SELECT sname,age
FROM student
WHERE sex='男' AND age > (
SELECT max(age)
FROM student
WHERE sex='女'
)
;

//数据库创建，删除，进入数据库
4：CREATE DATABASE `testdatabase`;
5: CREATE DATABASE `testdatabase`;
6：DROP DATABASE `testdatabase`;
7: CREATE DATABASE `testdatabase`;
8: USE testdatabase;
9: CREATE DATABASE `testdatabase2`;
10: USE DATABASE testdatabase2;
11: USE `testdatabase2`;
12: USE `testdatabase`;
13: DROP DATABASE `testdatabase2`;

//表的创建和删除，创建表同时设置属性
14: CREATE TABLE table1;
15: CREATE TABLE table1(No INT);
16: CREATE TABLE table2 (No INT,name VARCHAR(20),sex boolean);
17: DROP TABLE table1,table2;
18: CREATE TABLE tt1 (id INT(11) primary key);
19: CREATE TABLE tt2 (id int primary key, name varchar(20) unique, age int not null, sex boolean default '1');
//boolean 实际上是一个int，因此值为0或1
20：CREATE TABLE tt3 (id int primary key, age int not null auto_increment);
21: CREATE TABLE tt3 (id int primary key auto_increment, age int not null);
//一个表只能有一个auto_increment约束，且约束的属性必须是主键或主键的一部分
22：show tables;
23：drop table tt1,tt2,tt3;show tables;

//key键：
//主键：
24：create table tt1 (id int primary key);
25: create table tt2 (id int,name varchar(20),primary key (id));
26: create table tt3 (id int,name varchar(20),age int,primary key(id,name));
27: create table tt4(id int primary key,age int primary key);//只可以有一个主键
28: drop table tt1,tt2,tt3,tt4;

//外键：
29: create table tt1(id int(4),uid int(4));
30: create table tt2(id int(4),uid int(4),constraint nickname foreign key(uid) references tt1(uid));
31: drop table tt1;
create table tt1(id int,uid int,primary key(id,uid));
32: create table tt2(id int,uid int,constraint nickname foreign key(uid) references tt1(id));
//由上四条可知外键必须依赖于父表的主键上
33：create table tt2(id int(4),uid int(4),constraint nickname foreign key(uid) references tt1(id));
//外键连接必须连接的是主表的主键，如果连接主表主键的一部分，必须连接主键的第一个字段
34: create table tt3(id int,uid int,constraint nick name foreign key(id) references tt1(id));
35: drop table tt1,tt2,tt3;//此处会报错，因为有外键依赖要先删子表才能删父表，如果输入drop table tt3,tt2,tt1;则不会报错

36: create table tt1(Id int unsigned,uid int,primary key(id));
37: create table tt2(id int,uid int,constraint nickname foreign key (uid) references tt1(id));
38: create table tt2(id int,uid int unsigned,constraint foreign key (uid) references tt1(id));
//外键关联的主从表字段数据类型必须完全一样，否则报错“foreign key constraint is incorrectly formed”

//查看表：
39：describe tt1;
describe tt2;
40: desc tt1;
desc tt2;
41: show create table tt1;
show create table tt2;
42: show create table tt1 \G
show create table tt2 \G

//修改表：
//修改表名
43：alter table tt1 rename tt2;
44: alter table tt1 rename temp;
45: desc tt1;
desc temp;
46: alter table temp rename to tt1;
47: drop table tt1,tt2;

//修改表属性数据类型
48: create table tt1(id int,name varchar(20));
49: alter table tt1 modify id varchar(20);
50: insert into tt2(id,name) values(1,'string');//插入和删除操作还没有涉及，在这里只是为了加入一条数据已说明下面的问题
51：alter table tt1 modify name int;//有值的情况下转换字段类型失败，因为字符串类型无法自动转型为整数类型
52：delete from tt1；//删除表中元素
53: alter table tt1 modify name int;
desc tt1;

//修改表属性
54：alter table tt1 change name newname int;
desc tt1;
55: alter table tt2 change newname name varchar(20);
desc tt2;

//增加字段
56: alter table tt1 add name tinytext after id;
desc tt1;
57: alter table tt1 add age int not null after id;desc tt1;
58: alter table tt1 add no int unique first;desc tt1;

//删除字段
59：alter table tt1 drop age;desc tt1;desc tt1;

//修改属性排列顺序
60：alter table tt1 modify no int after name;desc tt1;
61: alter table tt1 modify no int first;desc tt1;
62: drop table tt1,tt2;

//索引：
//创建带索引的数据库表
63：create table tt1(id int,name varchar(20),age int,index index1(id));
64: show create table tt1\G
65: explain select * from tt1 where id=1;//explain语句用来查看索引详细情况，参考博文：http://blog.csdn.net/zhuxineli/article/details/14455029
66：create table tt2(id int,name varchar(20),age int,unique index index2(id));//唯一索引，唯一索引指的是被索引的字段值唯一
67: show create table tt2\G
68: create table tt3(id int,name varchar(20),age int,fulltext index index3(id));//全文索引
69: create table tt3(id int,name varchar(20),age int,fulltext index index3(name));
70: show create table tt3\G
71: create table tt4(id int,age int,info varchar(50),index index4(info(10)));
72: show create table tt4\G
73: create table tt5(id int,name varchar(20),info varchar(50),index index5 (id,name));
74: show create table tt5\G
75: explain select * from tt5 where name="nnn"\G
76: explain select * from tt5 where id='1'\G

//在已存在表上添加索引
//create [unique|fulltext|spatial] index indexname on tablename (columnname [(length)] [ASC|DESC]);

77: drop database testdatabase;
create database testdatabase;
use testdatabase;
78: create table tt1(id int,name varchar(20));
79: create index index1 on tt1 (id);
80: create index index1 on tt1 (name);//同一表的索引别名不能相同
81: create index index2 on tt1 (name);
82: drop index index2 on tt1;
83: create table tt2(id int,name varchar(20),age int,sex boolean,info varchar(50));
84: create index index1 on tt2 (id);//不同表的索引别名可以相同
85：create unique index index2 on tt2 (id);//不同索引可以重复使用相同字段
86: create fulltext index index3 on tt2 (name);
87: create index index4 on tt2 (sex,age);//多字段索引
88：show create table tt2;
89: drop table tt1,tt2;
90: show tables;

//Alter语句添加索引
//Alter table tablename add [unique|fulltext|spatial] index indexname (columename [(length)] [ASC|DESC]);
91: create table tt1(id int);
92: alter table tt1 add index index1 (id);
93: create table tt2 (id int,age int,name varchar(20),sex boolean, info varchar(50));
94：alter table tt2 add index index2 (id,name);
95: alter table tt2 add unique index index3 (sex);
96: alter table tt2 add index index4 (info(10));
97: alter table tt2 add fulltext index index5 (info(10));
show create table tt2;

//删除索引
98: drop index index1 on tt2;
show create table tt2;//观察删除索引后的表信息
99：drop table tt1,tt2;
100: exit
//完成第一阶段练习撒花

//第二阶段

//重建数据库
101, create database testdatabase;use database testdatabase;
102, create table tt1(id int, name varchar(20),age int,sex boolean);
103, show tables;desc tt1;

//插入
104, insert into tt1 values(1,"zhang",25,0);
105, insert into tt1 values(2,"wang",25,1);
106, select * from tt1;
107, insert into tt1(id,name,age,sex) values(3,"li",28,1);
108, insert into tt1(id,name,sex,age) values(4,"sun",0,22);
109, insert into tt1(id,name,sex) values(5,"zhao",30,1);
110, insert into tt1(id,age,name) values(6,"he",47,0);
111, insert into tt1(id,age,name) values(7,"chen",22,1),(7,"zhang",22,1),(7,"xie",32,1);
112, select * from tt1;

//修改
113, update tt1 set id=10,name="new",age=100,sex=0 where id=1; select * from tt1;
114, update tt1 set id=11,name="new" where id=2,age=25; select *from tt1;
115, update tt1 set id=12,sex=1 where id=7; select * from tt1;
116, update tt1 set sex=1 where id>3;
117, update tt1 set sex=0 where id<4;

//删除
118, delete from tt1 where id=1;select * from tt1;
119, delete from tt1 where id=12;select * from tt1;

//查询
120, alter table tt1 add address varchar(30);
121, update tt1 set address="Beijing" where sex=1;
122, update tt1 set address="Shanghai" where sex=0;
//简单查询
123, select id from tt1;
124, select id,name from tt1;
125, select id,name,address from tt1;
//条件查询
126, select id,name,address from tt1 where address="Beijing";
127, select * from tt1 where id in(2,3,4);
128, select * from tt1 where id not in(2,3,4);
129, select * from tt1 where id between 2 and 5;
130, select * from tt1 where id not between 2 and 5;
131, select * from tt1 where address like "beijing";
132, select * from tt1 where address like "bei";
133, select * from tt1 where address like "bei%";
134, select * from tt1 where address not like "bei%";
135, select * from tt1 where address is null;
136, select * from tt1 where address is not null;
137, select * from tt1 where age<20 and sex=1;
138, select * from tt1 where sex=0 or age>30;
//查询结果不重复
139, select distinct address from tt1;
//查询结果排序
140, select * from tt1 order by age;
141, select * from tt1 order by age asc;
142, select * from tt1 order by age desc;
//分组查询
143, select * from tt1 group by sex;//单独使用group by 只会选择每个分组的一条记录
//group by 与 group_concat结合使用
144, select group_concat(name),sex from tt1 group by sex;
145, select group_concat(name),group_concat(age),sex from tt1 group by sex;
146, select group_concat(name,age),sex from tt1 group by sex;
//group by与集合函数结合使用
147, select sex,count(sex) from tt1 group by sex;
148, select sex,count(sex) from tt1 group by sex having sex>2;//having用于对分组后的结果加限制条件
149, select sex,count(sex) from tt1 group by sex having count(sex)>2;
//with rollup
150, select sex,count(sex) from tt1 group by sex with rollup;//在显示记录的最后一行加一条，记录是上面所有记录的和，通常用于合计数量
//limit显示限制
151, select * from tt1;
152, select * from tt1 limit 2;
153, select * from tt1 limit 3;
154, select * from tt1 limit 0,2;
155, select * from tt1 limit 1,2;
//使用集合函数查询
//为了更好的理解本问题，新建一个表
156, create table grade(id int,name varchar(10),subject varchar(10),score int,sex boolean);
157, insert into grade values(1,"wang","math",100,1),(1,"wang","english",96,1),(1,"wang","physics",90,1);
insert into grade values(2,"li","math",96,1),(2,"li","english",85,1),(2,"li","physics",99,1);
insert into grade values(3,"sun","math",85,0),(3,"sun","english",98,0),(3,"sun","physics",80,0);
158, select * from grade;
159, select count(*) from grade;
160, select id,name,sum(score) from grade where id=1;
161, select id,name,sun(score) from grade group by id;
162, select id,name,sum(score) from grade group by id order by sum(score) desc;
163, select id,name,avg(score) from grade where id=2;
164, select id,name,avg(score),sum(score) from grade where id =3;
165, select id,name,avg(score) from grade group by id;
166, select subject,avg(score) from grade group by subject;* from
167, select subject,avg(score) from grade group by subject order by avg(score);
168, select name,max(score) from grade where subject="math";
169, select name,max(score) from grade where subject="english";
//连接查询
//内连接
170, create table stu(id int,name varchar(10),age int,sex boolean);
171, insert into stu values(1,"wang",25,1),(2,"li",23,1),(3,"sun",23,0),(4,"zhou",27,1),(5,"zhang",22,0);
172, select id,name,age,sex,score from stu,grade where stu.id=grade.id;
173, select stu.id,stu.name,stu.age,stu.sex,score from stu,grade where stu.id=grade.id;
174, select stu.id,stu.name,stu.age,stu.sex,score from stu,grade where stu.id=grade.id and score>90;
//外连接
175, select stu.id,stu.name,stu.age,stu.sex,score from stu left join grade on stu.id=grade.id;
176, select stu.id,stu.name,stu.age,stu,sex,score from stu right join grade on stu.id=grade.id;
177, insert into grade values(4,"hu","math",99,1),(5,"liu","english",97,0);
178, select stu.id,stu.name,stu.age,stu.sex,subject,score from stu left join grade on stu.id=grade.id;
179, select stu.id,stu.name,stu.age,stu.sex,subject,score from stu right join grade on stu.id=grade.id;
//子查询
180, select * from stu where id in (select *from grade);
181, select * from grade where id in (select * from stu);
182, create table scholarship(level int,money int,score int);
183, insert into scholarship values(1,10000,90),(2,5000,85),(3,3000,80);
184, select id,name,score from grade where score>=(select score from scholarship where level=1);
185, select id,name,score from grade where score>=(select min(score) from scholarship);
//exists子查询
186, select * from stu where exists (select name from grade where id=1);
187, select * from grade where score>any(select score from scholarship);
188, select * from grade where score>all(select score from scholarship);
//合并查询结果
189, select name from stu union select name from grade;
190, select name from stu union all select name from grade;
//别名
191, select * from scholarship s where s.level=1;
192, select * from scholarship s where s.money=5000;
193, select s.name from stu s,grade g where s.name=g.name;
194, select subject as su,score as sc from grade;
195, select * from stu where name regexp "^w";
196, select * from stu where name regexp "g$";
197, select * from stu where name regexp "^w.g$";
198, select * from stu where name regexp "^w..g$";
199, select * from stu where name regexp "[aeo]";
200, select * from stu where name regexp "[a-g]";

#建学生信息表student
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)

);
#建立教师表
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

);
#建立课程表course
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)

);
#建立成绩表
create table score
(
sno varchar(20) not null primary key,
foreign key(sno) references student(sno),
cno varchar(20) not null,
foreign key(cno) references course(cno),
degree decimal

);

#添加学生信息
insert into student values('108','曾华','男','1977-09-01','95033');
insert into student values('105','匡明','男','1975-10-02','95031');
insert into student values('107','王丽','女','1976-01-23','95033');
insert into student values('101','李军','男','1976-02-20','95033');
insert into student values('109','王芳','女','1975-02-10','95031');
insert into student values('103','陆君','男','1974-06-03','95031');

#添加教师表
insert into teacher values('804','李诚','男','1958-12-02','副教授','计算机系');
insert into teacher values('856','张旭','男','1969-03-12','讲师','电子工程系');
insert into teacher values('825','王萍','女','1972-05-05','助教','计算机系');
insert into teacher values('831','刘冰','女','1977-08-14','助教','电子工程系');

#添加课程表
insert into course values('3-105','计算机导论','825');
insert into course values('3-245','操作系统','804');
insert into course values('6-166','数字电路','856');
insert into course values('9-888','高等数学','831');
#添加成绩表

insert into score values('103','3-245','86');
insert into score values('105','3-245','75');
insert into score values('109','3-245','68');
insert into score values('103','3-105','92');
insert into score values('105','3-105','88');
insert into score values('109','3-105','76');
insert into score values('103','3-105','64');
insert into score values('105','3-105','91');
insert into score values('109','3-105','78');
insert into score values('103','6-166','85');
insert into score values('105','6-166','79');
insert into score values('109','6-166','81');

1、查询Student表中的所有记录的Sname、Ssex和Class列。

1

select Sname,Ssex,Class from student

2、查询教师所有的单位即不重复的Depart列。

1

select distinct Depart from teacher

3、查询Student表的所有记录。

1

select * from student

4、查询Score表中成绩在60到80之间的所有记录。

1

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。

1

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。

1

select * from Student where class='95031' or Ssex='女'

7、以Class降序查询Student表的所有记录。

1

select * from student order by class desc

8、以Cno升序、Degree降序查询Score表的所有记录。

1

select * from Score order by cno asc,degree desc

9、查询“95031”班的学生人数。

1

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）

1

select Sno,Cno from Score where Degree=(select max(Degree) from Score)

1

select Sno,Cno from Score order by Degree desc limit 0,1

11、查询每门课的平均成绩。

1

select Cno,avg(degree) 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。

1

select avg(Degree) from score where Cno like '3%' and Cno in (select Cno from score group by Cno having count(*)>=5) 用in 不用= 是因为可能会有多个

1

简单写法：select avg(Degree) from score where Cno like '3%' and group by Cno having count(*)>=5

13、查询分数大于70，小于90的Sno列。

1

select Sno from Score where degree>70 and degree<90

14、查询所有学生的Sname、Cno和Degree列。

1

select Sname, Cno,Degree from Score , student where Score.Sno=student.Sno

15、查询所有学生的Sno、Cname和Degree列。

1

select Sno,Cname,Degree from Score , Course where Score.Cno=Course.Cno

16、查询所有学生的Sname、Cname和Degree列。

1

select Sname,Cname,Degree from student,course,score where student.Sno=score.Sno and course.Cno=score.Cno

1

join .. on 写法：select 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。

1

select avg(degree) as 'class=95033' from Score where Sno in (select Sno from Student where Class='95033' ) 　

18、假设使用如下命令建立了一个grade表：

create table grade(low int(3),upp int(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’)

现查询所有同学的Sno、Cno和rank列。

1

select Sno,Cno,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。

1

109同学，选修是3-105课的

1

select * from score where Cno='3-105' and degree>(select max(degree ) from Score where Sno='109' and Cno='3-105' )

1

109同学，没有选修3-105课

1

select * from score where Cno='3-105' and degree>(select max(degree ) from Score where Sno='109')

and degree<( select max(degree ) from Score where sno in (select Sno from score group by Sno having count(*)>1))

1

选了多门课程并且是这个课程下不是最高分的

1

select * from score a where Sno in (select Sno from score group by Sno having count(*)>1) and degree<( select max(degree ) from Score b where b.cno = a.cno)

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。

1

Select * from score where degree>(select degree from Score where Sno='109' and Cno='3-105' )

22、查询和学号为108、101的同学同年出生的所有学生的Sno、Sname和Sbirthday列。

1

select sno,sname,sbirthday from student where year(sbirthday) = (select year(sbirthday) from student where sno='108')

1

select sno,sname,sbirthday from student where year(sbirthday) = (select year(sbirthday) from student where sno='101')

23、查询“张旭“教师任课的学生成绩。

1

select Sno,degree from score,Course where score.Cno=Course.Cno and Course.Tno= (select Tno from Teacher where Tname='张旭' )

1

select degree from score where Cno in (select cno from course where Tno= (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。

1

select Tname from Teacher, Course where Teacher.Tno=Course.Tno and Course.Cno =(select Cno from Score group by Cno having count(*)>5)

1

select Tname from Teacher where tno=( select Tno from Course where cno=( 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。

1

select * from student where class in ('95033','95031')

26、查询存在有85分以上成绩的课程Cno.

1

select Cno from score where degree>85

27、查询出“计算机系“教师所教课程的成绩表。

1

select * from course 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。

1

select Tname,Prof from Teacher where Depart ='计算机系' and Prof not in( select Prof from Teacher where Depart ='电子工程系') union select Tname,Prof from Teacher where Depart ='电子工程系' and Prof not in( select Prof from Teacher where Depart ='计算机系')

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。

any:代表括号中任意一个成绩就可以

1

select Cno,Sno,Degree from score where cno='3-105' and degree >any(select degree from score where cno='3-245' ) order by degree desc

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.

all:代表括号中的所有成绩

1

select Cno,Sno,Degree from score where cno='3-105' and degree >all(select degree from score where cno='3-245' ) order by degree desc

31、查询所有教师和同学的name、sex和birthday.

1

select tname,tsex,tbirthday from Teacher union select sname,ssex,sbirthday from Student

32、查询所有“女”教师和“女”同学的name、sex和birthday.

1

select Tname,Tsex,Tbirthday from Teacher where Tsex='女' union select Sname,Ssex,Sbirthday from Student where Ssex='女'

33、查询成绩比该课程平均成绩低的同学的成绩表。

1

select * from score a where degree < (select avg(degree) from score b where b.cno=a.cno)

34、查询所有任课教师的Tname和Depart.

1

select Tname,Depart from Teacher where tno in (select tno from course )

35 、查询所有未讲课的教师的Tname和Depart.

1

select Tname,Depart from Teacher where Tno not in (select Tno from Course where cno in (select cno from score ))

36、查询至少有2名男生的班号。

1

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。

1

select * from Student where Sname not like '王%%'

38、查询Student表中每个学生的姓名和年龄。

1

select Sname, year(now())-year(sbirthday) from Student

39、查询Student表中最大和最小的Sbirthday日期值。

1

select Max(Sbirthday ),Min(Sbirthday ) 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。

1

select * from Student order by class desc, Sbirthday

41、查询“男”教师及其所上的课程。

1

select Tname,Cname from course,teacher where course.tno= teacher.tno and teacher.Tsex='男'

42、查询最高分同学的Sno、Cno和Degree列。

1

select Sno,Cno,Degree from score where degree=(select max(degree) from score)

排序写法：

1

select Sno,Cno,Degree from score order by degree desc limit 0,1

43、查询和“李军”同性别的所有同学的Sname.

1

select Sname from Student where Ssex = (select Ssex from Student where Sname='李军')

44、查询和“李军”同性别并同班的同学Sname.

1

select Sname from Student where Ssex = (select Ssex from Student where Sname='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。

1

select Sno,Cno,degree from score where Cno=( select Cno from course where Cname='计算机导论') and Sno in (select Sno from student where Ssex='男')

好文要顶

#查看服务器中的数据库
SHOW DATABASES;

#创建一个数据库
CREATE DATABASE IF NOT EXISTS test;

#使用test数据库
USE test;

#建表
-- 表名丌能超过 30 个字符
-- 表名、列名是自由定义的
-- 所有的 SQL 语句都是以“ ; ”结尾
CREATE TABLE user_test(
id int,
password varchar(6),
name varchar(20),
phone varchar(11),
email varchar(20)
)；

#修改表的某一列
alter table user_test modify email varchar(50);

#插入数据
insert into user_test values(1001,'123456','张三','13468857714','linglongxin24@163.com');

#查询数据
SELECT * from user_test;

#查看表结构
desc user_test;

#查询姓名为张三的记录
SELECT name FROM user_test where name='张三';

#创建部门表
CREATE TABLE dept_test(
dept_id int(2),
dept_name CHAR(20),
dept_location CHAR(20)
);

#查看部门表结构
desc dept_test;

#给部门表插入数据
INSERT INTO dept_test VALUES(10,'developer','beijing');
INSERT INTO dept_test VALUES(20,'account','shanghai');
INSERT INTO dept_test VALUES(30,'sales','guangzhou');
INSERT INTO dept_test VALUES(40,'operations','tianjin');

#查看部门表数据
SELECT * FROM dept_test;

#创建员工表
CREATE TABLE emp_test(
emp_id INT(4),
name VARCHAR(20),
job VARCHAR(20),
salary FLOAT(7,2),
bonus FLOAT(7,2),
hire_date DATE,
manager INT(4),
dept_test_id INT(2)
);

#查看员工表结构
DESC emp_test;

#查看员工表数据
SELECT * FROM EMP_TEST;

#格式化日期用DATE_FORMAT(date,format)和Oracle有区别，Oracle使用用TO_DATE(ch, fmt)
INSERT INTO emp_test VALUES(1001,'张无忌','Manager','10000','2000',DATE_FORMAT('2010-01-12','%y-%m-%d'),1005,10);
INSERT INTO emp_test VALUES(1002,'刘苍松','Analyst', 8000 , 1000 ,DATE_FORMAT('2011-01-12','%y-%m-%d'),1001,10);
INSERT INTO emp_test VALUES(1003, '李翊' ,'Analyst',9000 , 1000 ,DATE_FORMAT('2010-02-11','%y-%m-%d'),1001,10);
INSERT INTO emp_test VALUES(1004,'郭芙蓉','Programmer',5000, NULL ,DATE_FORMAT('2010-02-11','%y-%m-%d'),1001,10);
INSERT INTO emp_test VALUES(1005 , '张三丰' , 'President' ,15000 , NULL ,DATE_FORMAT('2008-02-15','%y-%m-%d'),NULL,20);
INSERT INTO emp_test VALUES(1006 , '燕小六' , 'Manager' ,5000 ,400 ,DATE_FORMAT('2009-02-12','%y-%m-%d') , 1005 , 20);
insert into emp_test values(1007 , '陆无双' , 'clerk' ,3000 , 500 , DATE_FORMAT('2009-02-01','%y-%m-%d') , 1006 , 20) ;
insert into emp_test values(1008 , '黄蓉' , 'Manager' ,5000 , 500 , DATE_FORMAT('2009-11-01','%y-%m-%d') , 1005 , 30) ;
insert into emp_test values(1009 , '韦小宝' , 'salesman' ,4000 , null , DATE_FORMAT('2009-05-20','%y-%m-%d') , 1008 , 30) ;
insert into emp_test values(1010 , '郭靖' , 'salesman' ,4500 , 500 , DATE_FORMAT('2009-10-10','%y-%m-%d') , 1008 , 30) ;

#查看员工表数据
SELECT * FROM emp_test;

#查看部门表数据
SELECT * FROM dept_test;

#查看员工姓名、月薪、年薪
SELECT name,salary,salary*12 year_salary
FROM emp_test;

#查看员工姓名、月薪、奖金、月实发工资
#非空判断用IFNULL(expr1,expr2)和Oracle有区别，Oracle用NVL(expr1, expr2)
SELECT name,salary,bonus,salary+ IFNULL(bonus,0) month_salary
FROM emp_test;
INSERT INTO emp_test (emp_id,name) VALUES(1011,'于泽成');

#查询 emp_test 表 , 如果没有职位 , 显示'no position' , 如果有职位 , 显示员工的职位
SELECT name,IFNULL(job,'no positon') job
FROM emp_test;

#查询 emp_test 表 , 如果没有入职时间 , 显示为 2011 年 10 月 10 日 , 否则原样显示
SELECT name,IFNULL(hire_date,'2016-12-12') hire_date
FROM emp_test;

#连接字符串用CONCAT(str1,str2,...)和Oracle有区别，Oracle用||
SELECT emp_id,CONCAT(name,' job is ',job) detail
FROM emp_test;

#复制表
CREATE TABLE emp_test2 AS SELECT * FROM emp_test;
SELECT * FROM emp_test2;

#DISTINCT注意：distinct 必须( 只能 )跟在 select 后边，distinct 指所有列的唯一组合
#机构中有多少种职位？
SELECT DISTINCT job FROM emp_test;
#员工分布在哪些部门？
SELECT DISTINCT dept_test_id FROM emp_test;
#查询每个部门不重复的职位
SELECT DISTINCT job,dept_test_id FROM emp_test;

#薪水高亍 10000 元的员工数据？
SELECT * FROM emp_test WHERE salary>10000;

#职位是 Analyst 的员工数据？SQL 语句大小写丌敏感 , 数据大小写敏感
SELECT * FROM emp_test WHERE LOWER(job)='analyst';

#薪水大亍 5000 并且小亍 10000 的员工数据？>=<=；between and
SELECT * FROM emp_test WHERE salary>=5000 AND salary<=10000;
SELECT * FROM emp_test WHERE salary BETWEEN 5000 AND 10000;

#入职时间在 2011 年的员工？
#错误写法
SELECT * FROM emp_test WHERE hire_date=DATE_FORMAT('2011','%y');
#正确写法
SELECT * FROM emp_test WHERE hire_date BETWEEN DATE_FORMAT('2011-01-01','%y-%m-%d') AND DATE_FORMAT('2011-12-31','%y-%m-%d') ;

#列出职位是 Manager 或者 Analyst 的员工
SELECT * FROM emp_test WHERE job IN('Manager','Analyst');

#列出职位中包含有 sales 字符的员工数据？
SELECT * FROM emp_test WHERE LOWER(job) LIKE '%sales%'

#列出职位中第二个字符是 a 的员工数据？
SELECT * FROM emp_test WHERE LOWER(job) LIKE '_a%'

#查询数据库中有多少个名字中包含 'EMP' 的表？
#SELECT COUNT(*) FROM USER_TABLES WHERE TABLE_NAME LIKE '%EMP%';

insert into emp_test values(1012 , 'text_test' , 'salesman' ,4500 , 500 , DATE_FORMAT('2009-10-10','%y-%m-%d') , 1008 , 30) ;

SELECT * FROM emp_test;

#mysql-- 如果要查询的数据中有特殊字符( 比如_或% ),
-- 在做模糊查询时 ,
-- 需要加上\符号表示转义 , 如果是Oracle并且用 escape 短语指明转义字符\mysql不用
SELECT name FROM emp_test WHERE name LIKE '%\_%';
DELETE FROM emp_test WHERE emp_id=1012

#查询哪些员工没有奖金？
SELECT * FROM emp_test WHERE bonus IS NULL;

#薪水不在 5000 至 8000 的员工？
SELECT * FROM emp_test WHERE salary NOT BETWEEN 5000 AND 8000;

#不是部门 20 和部门 30 的员工？
SELECT * FROM emp_test WHERE dept_test_id NOT IN(20,30);

CREATE TABLE student (

id INT(10) NOT NULL UNIQUE PRIMARY KEY ,

name VARCHAR(20) NOT NULL ,

sex VARCHAR(4) ,

birth YEAR,

department VARCHAR(20) ,

address VARCHAR(50)

);

创建score表。SQL代码如下：

CREATE TABLE score (

id INT(10) NOT NULL UNIQUE PRIMARY KEY AUTO_INCREMENT ,

stu_id INT(10) NOT NULL ,

c_name VARCHAR(20) ,

grade INT(10)

);

为student表和score表增加记录
INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区');

INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区');

INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市');

INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市');

INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市');

INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市');

向score表插入记录的INSERT语句如下：

INSERT INTO score VALUES(NULL,901, '计算机',98);

INSERT INTO score VALUES(NULL,901, '英语', 80);

INSERT INTO score VALUES(NULL,902, '计算机',65);

INSERT INTO score VALUES(NULL,902, '中文',88);

INSERT INTO score VALUES(NULL,903, '中文',95);

INSERT INTO score VALUES(NULL,904, '计算机',70);

INSERT INTO score VALUES(NULL,904, '英语',92);

INSERT INTO score VALUES(NULL,905, '英语',94);

INSERT INTO score VALUES(NULL,906, '计算机',90);

INSERT INTO score VALUES(NULL,906, '英语',85);

mysql> SELECT * FROM student;

mysql> SELECT * FROM student LIMIT 1,3;

mysql> SELECT id,name,department FROM student;

mysql> SELECT * FROM student WHERE department IN ('计算机系','英语系');

mysql> SELECT id,name,sex,2013-birth AS age,department,address

-> FROM student

-> WHERE 2013-birth BETWEEN 18 AND 22;

mysql> SELECT id,name,sex,2013-birth AS age,department,address

-> FROM student

-> WHERE 2013-birth>=18 AND 2013-birth<=22;

mysql> SELECT c_name,MAX(grade) FROM score GROUP BY c_name;

mysql> SELECT c_name, grade

-> FROM score WHERE stu_id=

-> (SELECT id FROM student

-> WHERE name= '李四' );

mysql> SELECT student.id,name,sex,birth,department,address,c_name,grade

-> FROM student,score

-> WHERE student.id=score.stu_id;

mysql> SELECT student.id,name,SUM(grade) FROM student,score

-> WHERE student.id=score.stu_id

-> GROUP BY id;

mysql> SELECT c_name,AVG(grade) FROM score GROUP BY c_name;

mysql> SELECT * FROM student

-> WHERE id IN

-> (SELECT stu_id FROM score

-> WHERE c_name="计算机" and grade<95);

mysql> SELECT * FROM student

-> WHERE id =ANY

-> ( SELECT stu_id FROM score

-> WHERE stu_id IN (

-> SELECT stu_id FROM

-> score WHERE c_name= '计算机')

-> AND c_name= '英语' );

mysql> SELECT a.* FROM student a ,score b ,score c

-> WHERE a.id=b.stu_id

-> AND b.c_name='计算机'

-> AND a.id=c.stu_id

-> AND c.c_name='英语';

mysql> SELECT stu_id, grade

-> FROM score WHERE c_name= '计算机'

-> ORDER BY grade DESC;

mysql> SELECT id FROM student

-> UNION

-> SELECT stu_id FROM score;

mysql> SELECT student.id, name,sex,birth,department, address, c_name,grade

-> FROM student, score

-> WHERE

-> (name LIKE '张%' OR name LIKE '王%')

-> AND

-> student.id=score.stu_id ;

mysql> SELECT student.id, name,sex,birth,department, address, c_name,grade

-> FROM student, score

-> WHERE address LIKE '湖南%' AND

-> student.id=score.stu_id;

阅读全文

0 0