练习题，新建数据库anyun

一、新建数据库，数据库名为anyun

mysql> create database anyun;
Query OK, 1 row affected (0.00 sec)

二、查看数据库

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| anyun              |
| mysql              |
| performance_schema |
| qqq                |
+--------------------+
5 rows in set (0.00 sec)

三、使用数据库

mysql> use anyun;
Database changed

四、创建表

mysql> CREATE TABLE world(
    -> id INT NOT NULL AUTO_INCREMENT,
    -> name VARCHAR(100) NOT NULL,
    -> parent_id INT NOT NULL,
    -> level INT NOT NULL,
    -> PRIMARY KEY (id)
    -> )ENGINE=InnoDB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.43 sec)

五、查看表结构

mysql> desc world;
+-----------+--------------+------+-----+---------+----------------+
| Field     | Type         | Null | Key | Default | Extra          |
+-----------+--------------+------+-----+---------+----------------+
| id        | int(11)      | NO   | PRI | NULL    | auto_increment |
| name      | varchar(100) | NO   |     | NULL    |                |
| parent_id | int(11)      | NO   |     | NULL    |                |
| level     | int(11)      | NO   |     | NULL    |                |
+-----------+--------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

六、插入数据

mysql> insert into world(name,parent_id,level) values ('上海市',0,1),('北京市',0,1),('湖北省',0,2),('江苏省',0,1),('重庆市',0,2);
Query OK, 5 rows affected (0.02 sec)
Records: 5  Duplicates: 0  Warnings: 0

七、查询world表的所以数据

mysql> select * from world;
+----+-----------+-----------+-------+
| id | name      | parent_id | level |
+----+-----------+-----------+-------+
|  1 | 上海市    |         0 |     1 |
|  2 | 北京市    |         0 |     1 |
|  3 | 湖北省    |         0 |     2 |
|  4 | 江苏省    |         0 |     1 |
|  5 | 重庆市    |         0 |     2 |
+----+-----------+-----------+-------+
5 rows in set (0.00 sec)

八、使用Navicat查看

九、从world表里删除id=1的那行数据

mysql> delete from world where id = 1;
Query OK, 1 row affected (0.01 sec)

十、再查看world表里所以的数据，看看id=1的那一行删掉了没有

mysql> select * from world;
+----+-----------+-----------+-------+
| id | name      | parent_id | level |
+----+-----------+-----------+-------+
|  2 | 北京市    |         0 |     1 |
|  3 | 湖北省    |         0 |     2 |
|  4 | 江苏省    |         0 |     1 |
|  5 | 重庆市    |         0 |     2 |
+----+-----------+-----------+-------+
4 rows in set (0.00 sec)