MySQL的一些基本操作

Posted 2021-10-27 mqxnongmin

近期開始学习mysql，主要是通过书籍。和看燕十八老师的视频，然后通过博客记录自己的学习过程。

登入数据库

[email protected]:~$ mysql -uroot -p
Enter password: 

查看当前全部数据库

mysql> show databases;#查看当前全部数据库
+--------------------+
| Database?????????? |
+--------------------+
| information_schema |
| mysql????????????? |
| performance_schema |
+--------------------+
3 rows in set (0.00 sec)

创建数据库

mysql> create database ceshi;#创建数据库ceshi
Query OK, 1 row affected (0.00 sec)

mysql> show databases;#查看当前全部数据库。会看到如今多了一个ceshi
+--------------------+
| Database?????????? |
+--------------------+
| information_schema |
| ceshi????????????? |
| mysql????????????? |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)

查看数据库的定义

mysql> show create database ceshi;#查看数据库ceshi的定义
+----------+------------------------------------------------------------------+
| Database | Create Database????????????????????????????????????????????????? |
+----------+------------------------------------------------------------------+
| ceshi??? | CREATE DATABASE `ceshi` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+------------------------------------------------------------------+
1 row in set (0.00 sec)

删除数据库

mysql> drop database ceshi;#删除数据库ceshi
Query OK, 0 rows affected (0.07 sec)

mysql> show databases;#查看当前全部数据库，如今会发现ceshi已经不存在了。由于已经删除了
+--------------------+
| Database?????????? |
+--------------------+
| information_schema |
| mysql????????????? |
| performance_schema |
+--------------------+
3 rows in set (0.00 sec

使用数据库

mysql> create database ceshi_ku;#先建立一个库。等下用来建表
Query OK, 1 row affected (0.00 sec)

mysql> show databases;#ceshi_ku已经成功的建立了
+--------------------+
| Database           |
+--------------------+
| information_schema |
| ceshi_ku           |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)

mysql> use ceshi_ku;#建立表之前，首先要选择一个库
Database changed

查看当前库以下的全部表

mysql> show tables;#查看当前库以下的全部表。眼下是什么表也没有
Empty set (0.00 sec)

创建表

mysql> create table ceshi_biao
    -> (
    -> id int(11),
    -> salary float
    -> );#建立ceshi_biao表
Query OK, 0 rows affected (0.10 sec)

mysql> show tables;#查看当前库以下的全部表。ceshi_biao表已经成功建立
+--------------------+
| Tables_in_ceshi_ku |
+--------------------+
| ceshi_biao         |
+--------------------+
1 row in set (0.00 sec)

查看表基本结构

mysql> desc ceshi_biao;#查看ceshi_biao表基本结构
+--------+---------+------+-----+---------+-------+
| Field  | Type    | Null | Key | Default | Extra |
+--------+---------+------+-----+---------+-------+
| id     | int(11) | YES  |     | NULL    |       |
| salary | float   | YES  |     | NULL    |       |
+--------+---------+------+-----+---------+-------+
2 rows in set (0.04 sec)

查看表具体结构

mysql> show create table ceshi_biao;#查看ceshi_biao表具体结构
+------------+-------------------------------------------------------------------------------------------------------------------------------+
| Table      | Create Table                                                                                                                  |
+------------+-------------------------------------------------------------------------------------------------------------------------------+
| ceshi_biao | CREATE TABLE `ceshi_biao` (
  `id` int(11) DEFAULT NULL,
  `salary` float DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+------------+-------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

改动表名

mysql> alter table ceshi_biao rename to ceshi_new;#把ceshi_biao表的名字换成ceshi_new
Query OK, 0 rows affected (0.05 sec)

mysql> show tables;#查看当前库以下的全部表。ceshi_biao表的名字已经成功改为ceshi_new
+--------------------+
| Tables_in_ceshi_ku |
+--------------------+
| ceshi_new          |
+--------------------+
1 row in set (0.00 sec)

###########2种方法################

mysql> rename table ceshi_biao to ceshi_new;#把ceshi_biao表的名字换成ceshi_new
Query OK, 0 rows affected (0.03 sec)

mysql> show tables;#查看当前库以下的全部表。ceshi_biao表的名字已经成功改为ceshi_new
+--------------------+
| Tables_in_ceshi_ku |
+--------------------+
| ceshi_new????????? |
+--------------------+
1 row in set (0.00 sec)

往表里面插入数据

mysql> insert into? ceshi_new values 
??? -> (11,400.56),
??? -> (12,600.07),
??? -> (13,800.45);
Query OK, 3 rows affected (0.03 sec)
Records: 3? Duplicates: 0? Warnings: 0

mysql> select * from ceshi_new;#这个表就是员工号码以及员工的工资，刚才就仅仅插入了3条
+------+--------+
| id?? | salary |
+------+--------+
|?? 11 | 400.56 |
|?? 12 | 600.07 |
|?? 13 | 800.45 |
+------+--------+
3 rows in set (0.00 sec

清空表

mysql> truncate ceshi_new;#清空表，不是删除表
Query OK, 0 rows affected (0.04 sec)

mysql> select * from ceshi_new;#查看内容
Empty set (0.00 sec)

删除表

mysql> drop table ceshi_new;#删除ceshi_new表
Query OK, 0 rows affected (0.05 sec)

mysql> show tables;#查看当前库以下的全部表，ceshi_new表已经成功删除
Empty set (0.01 sec)

改动编码

mysql> set names utf8;#改动编码为utf8
Query OK, 0 rows affected (0.00 sec)