头歌MySQL数据库实训答案有目录 - ToB企服应用市场:ToB评测及商务社交产业平台

create table t_user1(
userId INT PRIMARY KEY,
name VARCHAR(32),
password VARCHAR(11),
phone VARCHAR(11),
email VARCHAR(32));

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create table t_user2(
name VARCHAR(32),
phone VARCHAR(11),
email VARCHAR(32),
PRIMARY KEY(name,phone));

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mysql -uroot -p123123 -h127.0.0.1

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create database MyDb;

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use MyDb;

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CREATE TABLE t_class
(
id INT PRIMARY KEY,
name VARCHAR(22)
);)

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CREATE TABLE t_student
(
id INT PRIMARY KEY,
name VARCHAR(22) ,
classId int,
CONSTRAINT fk_stu_class1 FOREIGN KEY(classId) REFERENCES t_class(id)
);

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mysql -uroot -p123123 -h127.0.0.1

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CREATE DATABASE MyDb;

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USE MyDb;

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CREATE TABLE t_user
(
id INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(32) NOT NULL UNIQUE,
sex VARCHAR(4) DEFAULT '男'
)DEFAULT CHARSET=utf8;

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USE Company;
########## Begin ##########
########## modify the table name ##########
ALTER TABLE tb_emp RENAME jd_emp;
########## show tables in this database ##########
show tables;
########## describe the table ##########
describe jd_emp;
########## End ##########

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## change the column name ##########
ALTER TABLE tb_emp change Id prod_id int(11);
########## change the data type of column ##########
ALTER TABLE tb_emp MODIFY Name varchar(30);
########## End ##########
DESCRIBE tb_emp;

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## add the column ##########
ALTER TABLE tb_emp ADD Country varchar(20) AFTER Name;
########## delete the column ##########
ALTER TABLE tb_emp DROP Salary;
########## End ##########
DESCRIBE tb_emp;

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## modify the column to top ##########
ALTER TABLE tb_emp MODIFY Name varchar(25) FIRST;
########## modify the column to the rear of another column ##########
ALTER TABLE tb_emp MODIFY DeptId int(11) AFTER Salary;
########## End ##########
DESCRIBE tb_emp;

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## delete the foreign key ##########
ALTER TABLE tb_emp DROP FOREIGN KEY emp_dept;
########## End ##########
SHOW CREATE TABLE tb_emp \G;

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## bundle insert the value #########
INSERT INTO tb_emp(Id,Name,DeptId,Salary)
VALUES (1,"Nancy",301,2300.00),
(2,"Tod",303,5600.00),(3,"Carly",301,3200.00);
########## End ##########
SELECT * FROM tb_emp;
########## End ##########

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## update the value ##########
UPDATE tb_emp
SET Name="Tracy",DeptId=302,Salary=4300.00
WHERE id=3;
########## End ##########
SELECT * FROM tb_emp;
########## End ##########
DESCRIBE tb_emp;

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## delete the value ##########
DELETE FROM tb_emp
WHERE Salary>3000;
########## End ##########
SELECT * FROM tb_emp;
########## End ##########
DESCRIBE tb_emp;

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## retrieving the Name and Salary ##########
select Name,Salary from tb_emp;
########## retrieving all the table ##########
select * from tb_emp;
########## End ##########

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## retrieving the Name and Salary with IN statement ##########
SELECT Name,Salary FROM tb_emp WHERE Id NOT IN (1);
########## End ##########

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USE Company;
#请在此处添加实现代码
########## Begin ##########
########## retrieving the Name and Salary with BETWEEN AND statement ##########
SELECT Name,Salary FROM tb_emp
WHERE Salary BETWEEN 3000 AND 5000;
########## End ##########

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USE Company;
######### Begin #########
SELECT Name,Salary FROM tb_emp WHERE Name LIKE "C%";
######### End #########

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USE Company;
######### Begin #########
SELECT * FROM tb_emp WHERE DeptId IS NULL;
######### End #########
######### Begin #########
SELECT DISTINCT Name FROM tb_emp;
######### End #########

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USE Company;
######### Begin #########
SELECT * FROM tb_emp WHERE DeptId=301 AND Salary > 3000;
######### End #########
######### Begin #########
SELECT * FROM tb_emp WHERE DeptId=301 OR DeptId=303;
######### End #########

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USE School;
#请在此处添加实现代码
########## Begin ##########
########## 查询1班同学的所有信息以成绩降序的方式显示结果 ##########
select * from tb_score where class_id = 1 order by score desc;
########## End ##########

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USE School;
#请在此处添加实现代码
########## Begin ##########
########## 对班级名称进行分组查询 ##########
SELECT * FROM tb_class GROUP BY class_id;
########## End ##########

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USE School;
#请在此处添加实现代码
########## Begin ##########
########## 查询班级中第2名到第5名的学生信息 ##########
SELECT * FROM tb_score order by score desc LIMIT 1,4;
########## End ##########

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USE School;
########## 查询数据表中学生姓名和对应的班级 ##########
#请在此处添加实现代码
########## Begin ##########
select tb_student.name as studentName,tb_class.name as className from tb_student join tb_class on tb_class.id = tb_student.class_id;
########## End ##########

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USE School;
########## 使用左外连接查询所有学生姓名和对应的班级 ##########
#请在此处添加实现代码
########## Begin ##########
select tb_student.name as studentName,tb_class.name as className
from tb_class right join tb_student on
tb_class.id=tb_student.class_id;
########## End ##########
########## 使用右外连接查询所有学生姓名和对应的班级 ##########
select tb_student.name as studentName,tb_class.name as className
from tb_class left join tb_student
on tb_class.id=tb_student.class_id;
#请在此处添加实现代码
########## Begin ##########
########## End ##########

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USE School;
########## 查询所有班级里分数在90分以上的学生的姓名和学生的成绩以及学生所在的班级 ##########
#请在此处添加实现代码
########## Begin ##########
select s1.name as studentName,score,
s2.name as className from tb_student as s1,
tb_class as s2 where s1.class_id=s2.id and
s1.score>90 order by score desc;
########## End ##########

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USE Company;
#请在此处添加实现代码
########## Begin ##########
#1.查询大于所有平均年龄的员工姓名与年龄
select name,age from tb_emp where age>(select avg(age) from tb_emp);
########## End ##########

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USE Company;
#请在此处添加实现代码
########## Begin ##########
#1.使用 ALL 关键字进行查询
SELECT position,salary FROM tb_salary WHERE salary >
ANY(SELECT max(salary) FROM tb_salary where position="java");
#2.使用 ANY 关键字进行查询
SELECT position,salary FROM tb_salary WHERE salary >
ANY(SELECT min(salary) from tb_salary where position="java");
#3.使用 IN 关键字进行查询
select position,salary from tb_salary where position in("java");
########## End ##########

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#请在此添加实现代码
########## Begin ##########
UPDATE tb_Salary
SET
sex = CASE sex WHEN "m" THEN "f"
ELSE "m"
END;
########## End ##########

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#请在此添加实现代码
########## Begin ##########
SELECT if(Id%2=0,Id-1,if(Id=5,Id,Id+1)) AS id,name
FROM tb_Seat ORDER BY Id;
########## End ##########

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#请在此添加实现代码
########## Begin ##########
select Score,(select count(distinct score) from score where score >=s.score) as Rank
from score as s order by Score desc;
select Score,(select count(*) from score as s2 where s2.score >s1.score)+1 as Rank
from score as s1 order by Rank;
########## End ##########

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#请在此添加实现代码
########## Begin ##########
select distinct a.* from gymnasium a,gymnasium b,gymnasium c
where a.visitors_flow>=100 and b.visitors_flow>=100
and c.visitors_flow>=100
and(
(a.id = b.id-1 and b.id = c.id - 1)or
(a.id = b.id-1 and a.id = c.id + 1)or
(a.id = b.id+1 and b.id = c.id + 1)
)
order by a.id;
########## End ##########

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#请在此添加实现代码
########## Begin ##########
select t1.classname,t1.chinese,t2.maths
from(select c.classname classname,sum(s.chinese)
chinese from tb_class c,tb_score s where c.stuname=
s.name and s.chinese>=60 group by c.classname)t1,
(select c.classname classname,sum(s.maths)maths from tb_class c,tb_score s
where c.stuname=s.name and s.maths>=60 group by c.classname)t2
where t1.classname=t2.classname;
########## End ##########

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#请在此添加实现代码
########## Begin ##########
select b.s_id,b.s_name,ROUND(AVG(a.s_score),2)as avg_score from student b
inner join score a on b.s_id = a.s_id
GROUP BY b.s_id,b.s_name HAVING avg_score <60
union
select a.s_id,a.s_name,0 as avg_score from student a
where a.s_id not in (select distinct s_id from score);
########## End ##########

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#请在此添加实现代码
########## Begin ##########
create view temp as(select s_id,group_concat(c_id)as c from score group by s_id);
select * from student where s_id in(select s_id from temp where c=(select c from temp where s_id="01")and s_id<>"01");
########## End ##########

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#请在此添加实现代码
########## Begin ##########
select a.*,count(b.s_score)+1 rank from score a left join score b
on a.c_id = b.c_id and a.s_score <b.s_score
group by a.c_id,a.s_id
order by a.c_id,count(b.s_score);
########## End ##########

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#请在此添加实现代码
########## Begin ##########
select a.*,b.s_score,b.c_id,c.c_name from student a
INNER JOIN score b ON a.s_id = b.s_id
INNER JOIN course c ON b.c_id = c.c_id
where b.c_id = (select c_id from course c,teacher d where c.t_id=d.t_id and d.t_name="张三")
and b.s_score in (select MAX(s_score)from score where c_id="02");
########## End ##########

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#请在此添加实现代码
########## Begin ##########
select a.s_id,a.s_name,ROUND(AVG(b.s_score))
avg_score from student a
inner join score b on a.s_id = b.s_id
where a.s_id in(
select s_id from score where s_score<60 GROUP BY s_id having count(*)>=2
)
GROUP BY a.s_id,a.s_name;
########## End ##########

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USE School;
#请在此处添加实现代码
########## Begin ##########
########## 查询该表中一共有多少条数据 ##########
select count(*) from tb_class;
########## 查询此表中367班有多少位学生 ##########
select classid,count(*) from tb_class where classid=367;
########## End ##########

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USE School;
#请在此处添加实现代码
########## Begin ##########
########## 查询所有学生总分数 ##########
select sum(score) from tb_class;
########## 查询学生语文科目的总分数 ##########
select course,sum(score) from tb_class where course="语文";
########## End ##########

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USE School;
#请在此处添加实现代码
########## Begin ##########
########## 查询学生语文科目的平均分数 ##########
select course,avg(score)from tb_class where course="语文";
########## 查询学生英语科目的平均分数 ##########
select course,avg(score) from tb_class where course="英语";
########## End ##########

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