Mysql practice questions 12.1
1. Create two tables as follows:
School table: id primary key increment, school name, school address
create table menpai(
id int primary key auto_increment,
mname varchar (20)，
msite varchar (20)
);
Personnel table: id primary key increment, name, age, mpid, number
create table mppeople (
id int primary key auto_increment,
name var char (20)，
age int (3),
mpid int (2),
num int(10)
);
2. Create a foreign key link for the two tables
alter table mppeople add constraint m_id foreign key (mpid) references menpai (id) ;
3. Insert the following data into the two tables:
| Huashan | Huashan |
|---|---|
| Beggar gang | Luoyang |
| Emei | Mount Emei |
| Wudang | Wudang Mountain |
| Mingjiao | Guangmingding |
| Shaolin | Shaolin Temple |
| Clear wind | 90 | 1 | 100001 |
|---|---|---|---|
| Yue Buqun | 50 | 1 | 100002 |
| Linghu Chong | 24 | 1 | 100003 |
| Hong Qigong | 70 | 2 | 100004 |
| Qiao Feng | 35 | 2 | 100005 |
| Madam Kill-all | 70 | 3 | 100006 |
| Zhou Zhiruo | 30 | 3 | 100007 |
| Wei Xiaobao | 20 | null | 100010 |
insert into menpai(mname,msite)
values('华山','华山'),
('丐帮','洛阳'),
('峨眉','峨眉山'),
('武当','武当山',
('明教','光明顶'),
('少林','少林寺');
insert into mppeople(name,age,mpid,num)
values('风清扬',90,1,100001)，
('岳不群',50,1,100002),
('令狐冲',24,1,100003),
('洪七公',70,2,100004),
('乔峰',35,2,100005),
('灭绝师太',70,3,100006),
('周芷若',20,3,100007),
('韦小宝',18, null, 100010);
4. Create the following query
(1) Query all the personnel information of the martial arts
select * from menpai left join mppeople on
menpai.id=mppeople.mpid;
(2) Query all personnel and display their martial arts information
select * from mppeople left join menpai on
mppeople.mpid=menpai.id;
(3) List the information of people who do not have martial arts
select menpai.mname,mppeople.name from mppeople left join menpai on
mppeople.mpid=menpai.id where mppeople.mpid is null;
(4) List the sects that no one has joined
select menpai.mname,mppeople.name from menpai left join
mppeople on menpai.id=mppeop le.mpid where mppeople. id
is null;