MySQL从创建数据库到删库跑路之旅

本文详细介绍MySQL数据库的基本操作流程,包括创建数据库、数据表、插入数据、更新数据等,并演示了如何进行字段增删改查等常见任务。

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约定以下库表及数据

数据库:testBB

数据表:boluochuixue

idnameageaddress
1菠萝吹雪10洛杉矶
1梨花诗12旧金山
2陆小果15伯克利
4上官子怡10奥克兰

MySQL从创建数据库到删库跑路之旅

阅读前必读:千万不要直接复制代码到mysql的shell中,经文章写完后的二次测试后,复制后有些sql语句会很奇怪的增加一些空格,建议手写,加强记忆

1、启动MySQL服务
net start mysql
2、登录MySQL
mysql -uroot -p
3、创建数据库testBB
create database testBB;
4、使用testBB库
use testBB;
5、在数据库testBB里创建数据表boluochuixue
create table boluochuixue(

​		id int,

​		name varchar(20),

​		age int,

​		address varchar(20)

);

查看以下刚刚创建的boluochuixue表的定义

desc boluochuixue;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| id      | int(11)     | YES  |     | NULL    |       |
| name    | varchar(20) | YES  |     | NULL    |       |
| age     | int(11)     | YES  |     | NULL    |       |
| address | varchar(20) | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
4 rows in set (0.00 sec)
6、创建约定的表的数据
insert into boluochuixue 

​		values (1,'菠萝吹雪',10,'洛杉矶'),(1,'梨花诗',12,'旧金山'),(2,'陆小果',15,'伯克利'),(4,'上官子怡',10,'奥克兰');

查看boluochuixue表中所有的数据

select * from boluochuixue;
+------+--------------+------+-----------+
| id   | name         | age  | address   |
+------+--------------+------+-----------+
|    1 | 菠萝吹雪     |   10 | 洛杉矶    |
|    1 | 梨花诗       |   12 | 旧金山    |
|    2 | 陆小果       |   15 | 伯克利    |
|    4 | 上官子怡     |   10 | 奥克兰    |
+------+--------------+------+-----------+
7、修改 梨花诗 的id为2,修改 陆小果 的id为3
update boluochuixue set id=2 where name='梨花诗';

update boluochuixue set id=3 where name='陆小果';

验证第七步是否修改成功

select * from boluochuixue;
+------+--------------+------+-----------+
| id   | name         | age  | address   |
+------+--------------+------+-----------+
|    1 | 菠萝吹雪     |   10 | 洛杉矶    |
|    2 | 梨花诗       |   12 | 旧金山    |
|    3 | 陆小果       |   15 | 伯克利    |
|    4 | 上官子怡     |   10 | 奥克兰    |
+------+--------------+------+-----------+
4 rows in set (0.00 sec)

结论:修改成功

8、在name字段后添加tel字段
alter table boluochuixue
		add tel int
        after name;
9、在address字段(最后一个字段后面)添加一个level字段
alter table boluochuixue
       add level varchar(20);

验证:用select语句,也可用desc语句查看定义

select * from boluochuixue;

+------+--------------+------+------+-----------+-------+
| id   | name         | tel  | age  | address   | level |
+------+--------------+------+------+-----------+-------+
|    1 | 菠萝吹雪     | NULL |   10 | 洛杉矶    | NULL  |
|    2 | 梨花诗       | NULL |   12 | 旧金山    | NULL  |
|    3 | 陆小果       | NULL |   15 | 伯克利    | NULL  |
|    4 | 上官子怡     | NULL |   10 | 奥克兰    | NULL  |
+------+--------------+------+------+-----------+-------+

4 rows in set (0.01 sec)
10、将所有的level字段都插入数据记录1
 update boluochuixue
 	  set level=1 ;

验证:用select语句

 select * from boluochuixue;
+------+--------------+------+------+-----------+-------+
| id   | name         | tel  | age  | address   | level |
+------+--------------+------+------+-----------+-------+
|    1 | 菠萝吹雪     | NULL |   10 | 洛杉矶    | 1     |
|    2 | 梨花诗       | NULL |   12 | 旧金山    | 1     |
|    3 | 陆小果       | NULL |   15 | 伯克利    | 1     |
|    4 | 上官子怡     | NULL |   10 | 奥克兰    | 1     |
+------+--------------+------+------+-----------+-------+
4 rows in set (0.00 sec)
11、特定位置修改tel字段
idnametel
1菠萝吹雪1001
2梨花诗1002
3陆小果1003
4上官子怡1004
update boluochuixue
    	 set tel=1001where id=1;

update boluochuixue set tel=1002 where id=2;

update boluochuixue set tel=1003 where id=3;

update boluochuixue set tel=1004 where id=4;

验证:用select 语句

+------+--------------+------+------+-----------+-------+
| id   | name         | tel  | age  | address   | level |
+------+--------------+------+------+-----------+-------+
|    1 | 菠萝吹雪     | 1001 |   10 | 洛杉矶    | 1     |
|    2 | 梨花诗       | 1002 |   12 | 旧金山    | 1     |
|    3 | 陆小果       | 1003 |   15 | 伯克利    | 1     |
|    4 | 上官子怡     | 1004 |   10 | 奥克兰    | 1     |
+------+--------------+------+------+-----------+-------+
4 rows in set (0.00 sec)
12、修改boluochuixue表名(这**太长了),修改为boluo

修改前先看一下,testBB数据库中的所有表

show tables;
+-----------------------+
| Tables_in_testBB |
+-----------------------+
| boluo                 |
| boluochuixue          |
| taobao                |
+-----------------------+
3 rows in set (0.00 sec)

发现竟然boluo表已经存在,那就先删掉boluo表,然后再修改boluochuixue为boluo

删除boluo表

drop table boluo;

验证boluo表是否删除

show tables;
+-----------------------+
| Tables_in_testBB|
+-----------------------+
| boluochuixue          |
| taobao                |
+-----------------------+
2 rows in set (0.00 sec)

结果:已经删除了boluo表

修改boluochuixue为boluo

alter table boluochuixue
     rename boluo;

验证:是否修改成功

show tables;
+-----------------------+
| Tables_in_testBB |
+-----------------------+
| boluo                 |
| taobao                |
+-----------------------+
2 rows in set (0.00 sec)
13、查看一下表的详细定义
show create table boluo;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                                                                                                                                        |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| boluo | CREATE TABLE `boluo` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(20) DEFAULT NULL,
  `tel` int(11) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  `address` varchar(20) DEFAULT NULL,
  `level` varchar(20) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
14、修改tel字段为phone
alter table boluo
      change tel phone int(12);

检验:desc boluo;

+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| id      | int(11)     | YES  |     | NULL    |       |
| name    | varchar(20) | YES  |     | NULL    |       |
| phone   | int(12)     | YES  |     | NULL    |       |
| age     | int(11)     | YES  |     | NULL    |       |
| address | varchar(20) | YES  |     | NULL    |       |
| level   | varchar(20) | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

结论:tel字段修改为phone成功

15、删除address字段信息(家庭住址太私密了,删掉)
alter table boluo
      drop address;

检验:用select或desc都可以

select * from boluo;
+------+--------------+-------+------+-------+
| id   | name         | phone | age  | level |
+------+--------------+-------+------+-------+
|    1 | 菠萝吹雪     |  1001 |   10 | 1     |
|    2 | 梨花诗       |  1002 |   12 | 1     |
|    3 | 陆小果       |  1003 |   15 | 1     |
|    4 | 上官子怡     |  1004 |   10 | 1     |
+------+--------------+-------+------+-------+
4 rows in set (0.00 sec)

结论:删除address字段成功

16、删除名字叫菠萝吹雪这个人的信息
delete from boluo
       where name='菠萝吹雪';

检验:用select语句

select * from boluo;
+------+--------------+-------+------+-------+
| id   | name         | phone | age  | level |
+------+--------------+-------+------+-------+
|    2 | 梨花诗       |  1002 |   12 | 1     |
|    3 | 陆小果       |  1003 |   15 | 1     |
|    4 | 上官子怡     |  1004 |   10 | 1     |
+------+--------------+-------+------+-------+
3 rows in set (0.00 sec)

检验:菠萝吹雪这条信息被成功删除

17、删除boluo表
drop table boluo;

检验:查看所有表

+-----------------------+
| Tables_in_testBB |
+-----------------------+
| taobao                |
+-----------------------+
1 row in set (0.00 sec)
18、删除testBB数据库
drop database testBB;
19、退出mysql
exit
20、退出MySQL服务
net stop mysql
21、数据库都删完了,还发呆呢?跑路哇

参考文章:Mysql基本语法篇-章节1
MySQL表数据的操作篇-章节3

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