SQL语句（数据库级别的命令集合）
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数据库内部存储结构
登录数据库
登录数据库
mysql -h服务器地址 -u用户名 -p密码(不安全的登录形式)
退出数据库
exit
以一种相对安全的方式进行登录
mysql -h服务器地址 -u用户名 -p回车+密码数据库用户相关的操作
# 查看用户
### mysql.user mysql数据库中user表示系统内置用于存放用户的
select User,Password,Host from mysql.user;
结果展示：
+------+----------+-----------+
| User | Password | Host |
+------+----------+-----------+
| root | | localhost |
| root | | 127.0.0.1 |
| root | | ::1 |
| | | localhost |
+------+----------+-----------+
4 rows in set (0.00 sec)
-----------------------------------------------------------------------------------------
#修改用户密码
set password for username@'localhost' = password('newpassword');
结果展示：密码是加过密的
+------+-------------------------------------------+
| user | password |
+------+-------------------------------------------+
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| root | |
| root | |
| | |
+------+-------------------------------------------+
4 rows in set (0.00 sec)
-----------------------------------------------------------------------------------------
#创建用户
create user "username"@"localhost" identified by "password"
结果展示：
+-------+-------------------------------------------+-----------+
| user | password | host |
+-------+-------------------------------------------+-----------+
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | localhost |
| root | | 127.0.0.1 |
| root | | ::1 |
| | | localhost |
| yiqi | | localhost |
| yiqi2 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | localhost |
+-------+-------------------------------------------+-----------+
6 rows in set (0.00 sec)
-----------------------------------------------------------------------------------------
#删除用户
delete from mysql.user where user="yiqi" and host="localhost";
结果展示：
+-------+-------------------------------------------+-----------+
| user | password | host |
+-------+-------------------------------------------+-----------+
| root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | localhost |
| root | | 127.0.0.1 |
| root | | ::1 |
| | | localhost |
| yiqi2 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | localhost |
+-------+-------------------------------------------+-----------+
5 rows in set (0.00 sec)
-----------------------------------------------------------------------------------------
#权限分配
grant all privileges on *.* to "yiqi2"@"localhost";
flush privileges;
结果展示： 你就只看是不是都由 N 变成了 Y
+-----------+-------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+
| Host | User | Password | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | Show_db_priv | Super_priv | Create_tmp_table_priv | Lock_tables_priv | Execute_priv | Repl_slave_priv | Repl_client_priv | Create_view_priv | Show_view_priv | Create_routine_priv | Alter_routine_priv | Create_user_priv | Event_priv | Trigger_priv | Create_tablespace_priv | ssl_type | ssl_cipher | x509_issuer | x509_subject | max_questions | max_updates | max_connections | max_user_connections | plugin | authentication_string |
+-----------+-------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+
| localhost | yiqi2 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | N | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | | | | | 0 | 0 | 0 | 0 | | NULL |
+-----------+-------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------+--------------+-----------+------------+-----------------+------------+------------+--------------+------------+-----------------------+------------------+--------------+-----------------+------------------+------------------+----------------+---------------------+--------------------+------------------+------------+--------------+------------------------+----------+------------+-------------+--------------+---------------+-------------+-----------------+----------------------+--------+-----------------------+
数据库基本操作
# 查询所有的数据库
show databases; #这里面一定要注意，这里有s
结果展示： 这四个数据库是安装后自动创建的
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.00 sec)
-----------------------------------------------------------------------------------------
# 创建数据库
create database 数据库的名称 [编码](可有可无，如果没有的话，就是这个服务器的默认编码)
效果展示：
### 未加编码的
mysql> create database wustyq; ### 千万不要加引号
Query OK, 1 row affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
| wustyq |
+--------------------+
5 rows in set (0.00 sec)
### 加编码的
mysql> create database my_database character set gbk;
Query OK, 1 row affected (0.00 sec)
mysql> show create database my_database;
+-------------+---------------------------------------------------------------------+
| Database | Create Database |
+-------------+---------------------------------------------------------------------+
| my_database | CREATE DATABASE `my_database` /*!40100 DEFAULT CHARACTER SET gbk */ |
+-------------+---------------------------------------------------------------------+
1 row in set (0.00 sec)
-----------------------------------------------------------------------------------------
# 查看当前数据库的编码
show create database 数据名称
结果展示：默认和安装时勾选的编码一致
mysql> show create database wustyq;
+----------+-------------------------------------------------------------------+
| Database | Create Database |
+----------+-------------------------------------------------------------------+
| wustyq | CREATE DATABASE `wustyq` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+-------------------------------------------------------------------+
1 row in set (0.00 sec)
-----------------------------------------------------------------------------------------
# 修改当前数据库的编码
alter database wustyq character set 编码形式
效果展示：
mysql> alter database wustyq character set utf8;
mysql> show create database wustyq;
+----------+-----------------------------------------------------------------+
| Database | Create Database |
+----------+-----------------------------------------------------------------+
| wustyq | CREATE DATABASE `wustyq` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+-----------------------------------------------------------------+
1 row in set (0.00 sec)
-----------------------------------------------------------------------------------------
# 删除数据库
drop database 数据库名称
效果展示：
mysql> drop database wustyq;
Query OK, 0 rows affected (0.09 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| my_database |
| my_db |
| mysql |
| performance_schema |
| test |
+--------------------+
6 rows in set (0.00 sec)
-----------------------------------------------------------------------------------------
# 修改数据库名称
rename database 旧的数据库名称 to 新的数据库名称（5.1.23之后被废弃了）
暴力方法：
首先，我们退出 mysql 然后 找到我们数据库安装目录的 data 下 找到我们的数据库 修改文件夹名称即可
效果展示：暴力修改的结果
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| my |
| mysql |
| performance_schema |
| test |
+--------------------+
5 rows in set (0.00 sec)
-----------------------------------------------------------------------------------------
# 切换数据库
use 数据库名称
效果展示：
mysql> use my;
Database changed
-----------------------------------------------------------------------------------------
# 查看当前使用的数据库
select database();
效果展示：
mysql> select database();
+------------+
| database() |
+------------+
| my |
+------------+
1 row in set (0.00 sec)
-----------------------------------------------------------------------------------------
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