十三周四次课

Posted 2020-10-28

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十三周四次课（3月22日）
13.1 设置更改root密码
13.2 连接mysql
13.3 mysql常用命令

13.1 设置更改root密码

设置更改root密码目录概要

/usr/local/mysql/bin/mysql -uroot
更改环境变量PATH，增加mysql绝对路径
mysqladmin -uroot password '123456'
mysql -uroot -p123456
密码重置
vi /etc/my.cnf//增加skip-grant
重启mysql服务 /etc/init.d/mysqld restart
mysql -uroot
use mysql;
update user set password=password('aminglinux') where user='root';

设置更改root密码

root用户是mysql的超级管理员用户，和linux系统的root用户类似，不过和Linux的不一样
默认mysql的 root 用户密码是空的，直接就可以连接上去，不需要输入密码，但是不安全，所以就需要设置一个密码
为了方便使用mysql服务，将mysql目录加入到环境变量里

1.打开系统，查看mysql是否启动

[[email protected] vhost]# ps aux |grep mysql

root 838 0.0 0.1 115388 1680 ? S 20:05 0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/tianqi-01.pid

mysql 998 0.0 46.0 981248 460236 ? Sl 20:05 0:02 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/data/mysql/tianqi-01.err --pid-file=/data/mysql/tianqi-01.pid --socket=/tmp/mysql.sock

root 4175 0.0 0.0 112664 984 pts/0 S+ 21:58 0:00 grep --color=auto mysql

[[email protected] vhost]#

2.若是没有启动mysql的话，将mysql启动起来

[[email protected] ~]# /etc/init.d/mysqld start

Starting MySQL [ OK ]

[[email protected] ~]# 180321 22:06:42 mysqld_safe A mysqld process already exists

[[email protected] ~]#

[[email protected] ~]# !ps

ps aux |grep mysql

root 838 0.0 0.1 115388 1680 ? S 20:05 0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/tianqi-01.pid

mysql 998 0.0 46.0 981248 460236 ? Sl 20:05 0:06 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/data/mysql/tianqi-01.err --pid-file=/data/mysql/tianqi-01.pid --socket=/tmp/mysql.sock

root 4418 0.0 0.0 112660 984 pts/1 R+ 22:08 0:00 grep --color=auto mysql

[[email protected] ~]#

3.在启动mysql后，使用mysql -uroot命令，但是mysql命令会提示不存在，因为安装的mysql是在/usr/local/mysql/bin/mysql，而这个目录并不在环境变量PATH里面，所以它会报错

[[email protected] ~]# mysql -uroot

-bash: mysql: command not found

[[email protected] ~]# ls /usr/local/mysql/bin/mysql

/usr/local/mysql/bin/mysql

[[email protected] ~]# echo $PATH

/usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

[[email protected] ~]#

4.若想要这个命令直接运行，需要把PATH做一个更改

[[email protected] ~]# export PATH=$PATH:/usr/local/mysql/bin/

[[email protected] ~]#

5.这时再来使用mysql -uroot命令就会发现可以使用了

退出mysql输入 quit 即可

[[email protected] ~]# mysql -uroot

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

6.若想要变量永久生效，还需要将export PATH=$PATH:/usr/local/mysql/bin/ 放入到 /etc/profile

//将内容放到配置文件的最后面，使命令永久生效

export PATH=$PATH:/usr/local/mysql/bin/

保存退出

7.假设若是没有运行 export PATH=$PATH:/usr/local/mysql/bin/ 命令，那也不能运行mysql，因为变量还没有生效，想要这个变量生效，在配置文件中加入命令后，还需要执行source /etc/profile 命令，重新加载

[[email protected] ~]# source /etc/profile

[[email protected] ~]#

8.一般是使用mysql -uroot -p命令

-p，表示指定密码

9.密码为空的时候，直接回车就可进入到mysql，并可以在其中操作一些mysql的一些行为

[[email protected] ~]# mysql -uroot -p

Enter password:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 2

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

10.退出mysql，输入 quit 即可

11.设置mysql密码，命令为mysqladmin -uroot passwd 'tianqi.1' 在 ' ' 为密码

[[email protected] ~]# mysqladmin -uroot password 'tianqi.1'

Warning: Using a password on the command line interface can be insecure.

[[email protected] ~]#

12.在设置密码的时候，会看到有输出信息，但这不是报错信息，这是告诉你你现在密码在当前命令行显示出来了，这样不×××全

13.这时在想直接登录mysql，就会提示需要输入密码了

[[email protected] ~]# mysql -uroot

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

14.再使用-p，并输入密码就可以正常的进入到mysql命令行了

[[email protected] ~]# mysql -uroot -p

Enter password:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 7

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

知道mysql的root密码，去更改密码

1.若是这时知道mysql密码，去修改mysql密码，看到输出的提示信息不用去理会

格式

mysqladmin -uroot -p'hanfeng.1' password 'hanfeng'

[[email protected] ~]# mysqladmin -uroot -p'tianqi.1' password 'tianqi.2'

Warning: Using a password on the command line interface can be insecure.

[[email protected] ~]#

2.指定新密码去登录，当然也可以不明文指定密码，直接-p回车，输入密码登录也行

[[email protected] ~]# mysql -uroot -p'tianqi.2'

Warning: Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 9

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

[[email protected] ~]# mysql -uroot -p

Enter password:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 11

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

3.在明文指定密码的时候，密码可以加单引号，也可以不加单引号，建议加上单引号，防止密码有特殊符号的存在——>（若是不加单引号，而密码中又有特殊符号，就有可能会不识别）

不知道mysql的root密码，去更改密码

1.在不知道mysql的root用户密码的时候，先去更改 /etc/my.cnf 下配置文件中加入skip-grant

skip-grant ，表示忽略授权，也就是说操作mysql的时候不需要用户名和密码了，能直接登录

[[email protected] ~]# vim /etc/my.cnf

//在[mysqld]下面

加入一行

skip-grant

保存退出

2.在更改配置文件后，重启mysql服务

[[email protected] ~]# /etc/init.d/mysqld restart

Shutting down MySQL... [ OK ]

Starting MySQL....... [ OK ]

[[email protected] ~]#

3.这时候再输入mysql -uroot ，会发现直接进入mysql，而不需要密码了

[[email protected] ~]# mysql -uroot

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

4.在登录进mysql后，还需要更改一个表，因为用户名和密码是存在于一个mysql库里面的，使用 use mysql; 切换库，在切换到mysql库里面，然后去更改一个存用户名密码的user表

use mysql; 切换库

mysql> use mysql

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql>

5.查看user表，输入select * from user; 命令，会看到输出乱七八糟的乱码，里面存放的就是用户名和密码，还有权限和授权等信息

mysql> select * from user;

………………

| Host | User | Password

………………

//省略指出都是乱码

6.查看password表，会看到密码都是加密的

mysql> select password from user where user='root';

+-------------------------------------------+

| password |

+-------------------------------------------+

| *1D6E44B005B8029764C395EE17EBA018CB2DD9A2 |

| |

+-------------------------------------------+

4 rows in set (0.05 sec)

mysql>

7.更改user表，使用update user set password=password('aminglinux') where user='root'; 命令

update user set password=password('aminglinux') where user='root';

密码字段函数 //用于加密密码高亮部分：为条件语句

mysql> update user set password=password('aminglinux') where user='root';

Query OK, 4 rows affected (0.10 sec)

Rows matched: 4 Changed: 4 Warnings: 0

mysql>

8.提示说4行修改完毕，即使有些行是空的

9.这样密码就更改成功了，输入quit退出数据库即可

mysql> quit

Bye

[[email protected] ~]#

10.再去 /etc/my.cnf 配置文件中删除免授权配置，即删除skip-grant——>若是不删除，那么之后所有的用户都不需要输入密码，就可以登录进去，这样安全性太低

[[email protected] ~]# vim /etc/my.cnf

//在[mysqld]下面删除刚添加的

skip-grant

保存退出

11.重启mysql服务

[[email protected] ~]# /etc/init.d/mysqld restart

Shutting down MySQL.. [ OK ]

Starting MySQL....... [ OK ]

[[email protected] ~]#

12.重启完之后，再用新的密码测试下，会看到新的密码可以登录

[[email protected] ~]# mysql -uroot -paminglinux

Warning: Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 1

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

13.这样就是成功更改mysql密码

13.2 连接mysql

连接mysql

本地连接——>即使没有指定，但默认使用sock连接，使用/tmp/mysql.sock连接

mysql -uroot -p123456 //输入用户名和密码连接本机

使用ip端口连接远程机器

mysql -uroot -p123456 -h[远程mysql主机IP] -P[端口]

[[email protected] ~]# mysql -uroot -paminglinux -h127.0.0.1 -P3306

Warning: Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 9

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

使用sock方式连接（只适合在本机使用）如为指定IP就用sock访问
mysql -uroot -p123456 -S/tmp/mysql.sock

[[email protected] ~]# mysql -uroot -paminglinux -S/tmp/mysql.sock

Warning: Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 10

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> quit

Bye

[[email protected] ~]#

连接mysql之后执行命令（常用于shell脚本）
mysql -uroot -p123456 -e “show databases”

show databases //列出所有数据库

[[email protected] ~]# mysql -uroot -paminglinux -e “show databases”

Warning: Using a password on the command line interface can be insecure.

+--------------------+

| Database |

+--------------------+

| information_schema |

| mysql |

| performance_schema |

| test |

+--------------------+

[[email protected] ~]#

13.3 mysql常用命令

mysql常用命令目录概要

查询库 show databases;
切换库 use mysql;
查看库里的表 show tables;
查看表里的字段 desc tb_name;
查看建表语句 show create table tb_name\G;
查看当前用户 select user();
查看当前使用的数据库 select database();
创建库 create database db1;
创建表 use db1; create table t1(id int(4), name char(40));
查看当前数据库版本 select version();
查看数据库状态 show status;
查看各参数 show variables; show variables like 'max_connect%';
修改参数 set global max_connect_errors=1000;
查看队列 show processlist; show full processlist;

mysql常用命令

mysql内部命令和linux系统命令不通用
库是由表组成，表是由字段组成
在mysql 中使用的命令需要使用分号 ; 结尾，否则会出问题

1.登录到mysql

[[email protected] ~]# mysql -uroot -paminglinux

Warning: Using a password on the command line interface can be insecure.

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 13

Server version: 5.6.35 MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

2.查看数据库 show databases;

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| mysql |

| performance_schema |

| test |

+--------------------+

4 rows in set (0.00 sec)

mysql>

3.切换库 use mysql; ——>切换到哪一个库下面

mysql> use mysql;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql>

4.列出所有的表 show tables;

mysql> show tables;

+---------------------------+

| Tables_in_mysql |

+---------------------------+

| columns_priv |

| db |

| event |

| func |

| general_log |

| help_category |

| help_keyword |

| help_relation |

| help_topic |

| innodb_index_stats |

| innodb_table_stats |

| ndb_binlog_index |

| plugin |

| proc |

| procs_priv |

| proxies_priv |

| servers |

| slave_master_info |

| slave_relay_log_info |

| slave_worker_info |

| slow_log |

| tables_priv |

| time_zone |

| time_zone_leap_second |

| time_zone_name |

| time_zone_transition |

| time_zone_transition_type |

| user |

+---------------------------+

28 rows in set (0.01 sec)

mysql>

5.查看表里的字段 desc tb_name;

6.例子

desc user; //查看user表里的所有字段；需要进入相关的库以后才能查看对应的表

//库是由表组成的，表是由字段组成的

mysql> desc user;

+------------------------+-----------------------------------+------+-----+-----------------------+-------+

+------------------------+-----------------------------------+------+-----+-----------------------+-------+

| Host | char(60) | NO | PRI | | |

| User | char(16) | NO | PRI | | |

| Select_priv | enum('N','Y') | NO | | N | |

| Insert_priv | enum('N','Y') | NO | | N | |

| Update_priv | enum('N','Y') | NO | | N | |

| Delete_priv | enum('N','Y') | NO | | N | |

| Create_priv | enum('N','Y') | NO | | N | |

| Drop_priv | enum('N','Y') | NO | | N | |

| Reload_priv | enum('N','Y') | NO | | N | |

| Shutdown_priv | enum('N','Y') | NO | | N | |

| Process_priv | enum('N','Y') | NO | | N | |

| File_priv | enum('N','Y') | NO | | N | |

| Grant_priv | enum('N','Y') | NO | | N | |

| References_priv | enum('N','Y') | NO | | N | |

| Index_priv | enum('N','Y') | NO | | N | |

| Alter_priv | enum('N','Y') | NO | | N | |

| Show_db_priv | enum('N','Y') | NO | | N | |

| Super_priv | enum('N','Y') | NO | | N | |

| Create_tmp_table_priv | enum('N','Y') | NO | | N | |

| Lock_tables_priv | enum('N','Y') | NO | | N | |

| Execute_priv | enum('N','Y') | NO | | N | |

| Repl_slave_priv | enum('N','Y') | NO | | N | |

| Repl_client_priv | enum('N','Y') | NO | | N | |

| Create_view_priv | enum('N','Y') | NO | | N | |

| Show_view_priv | enum('N','Y') | NO | | N | |

| Create_routine_priv | enum('N','Y') | NO | | N | |

| Alter_routine_priv | enum('N','Y') | NO | | N | |

| Create_user_priv | enum('N','Y') | NO | | N | |

| Event_priv | enum('N','Y') | NO | | N | |

| Trigger_priv | enum('N','Y') | NO | | N | |

| Create_tablespace_priv | enum('N','Y') | NO | | N | |

| max_questions | int(11) unsigned | NO | | 0 | |

| max_updates | int(11) unsigned | NO | | 0 | |

| max_connections | int(11) unsigned | NO | | 0 | |

| max_user_connections | int(11) unsigned | NO | | 0 | |

| password_expired | enum('N','Y') | NO | | N | |

+------------------------+-----------------------------------+------+-----+-----------------------+-------+

43 rows in set (0.03 sec)

mysql>

//Field就是代表了字段

7.查看建表语句 show create table tb_name\G;——>G 表示竖排显示

8.例子

show create table user\G;

mysql> show create table user\G

*************************** 1. row ***************************

Table: user

Create Table: CREATE TABLE `user` (

`Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '',

`User` char(16) COLLATE utf8_bin NOT NULL DEFAULT '',

`Password` char(41) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL DEFAULT '',

`Select_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Insert_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Update_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Delete_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Drop_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Reload_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Shutdown_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Process_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`File_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Grant_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`References_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Index_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Alter_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Show_db_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Super_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_tmp_table_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Lock_tables_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Execute_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Repl_slave_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Repl_client_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Show_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Alter_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_user_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Event_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Trigger_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`Create_tablespace_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

`ssl_type` enum('','ANY','X509','SPECIFIED') CHARACTER SET utf8 NOT NULL DEFAULT '',

`ssl_cipher` blob NOT NULL,

`x509_issuer` blob NOT NULL,

`x509_subject` blob NOT NULL,

`max_questions` int(11) unsigned NOT NULL DEFAULT '0',

`max_updates` int(11) unsigned NOT NULL DEFAULT '0',

`max_connections` int(11) unsigned NOT NULL DEFAULT '0',

`max_user_connections` int(11) unsigned NOT NULL DEFAULT '0',

`plugin` char(64) COLLATE utf8_bin DEFAULT 'mysql_native_password',

`authentication_string` text COLLATE utf8_bin,

`password_expired` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N',

PRIMARY KEY (`Host`,`User`)

) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Users and global privileges'

1 row in set (0.00 sec)

mysql>

//这样的结果比上面的表示还要详细

9.查看当前用户 select user();

mysql> select user();

+----------------+

| user() |

+----------------+

| [email protected] |

+----------------+

1 row in set (0.01 sec)

mysql>

这里的localhost 表示主机名，会反解析你的IP所属主机名

10.在mysql里面使用方向键可以查看之前使用的命令，和shell的命令类似，并且也有记录命令历史的功能，默认的缓存文件在 / 下，名字为“.mysql_history”

支持ctrl+l 清屏

[[email protected] ~]# ls -la

total 68

dr-xr-x---. 6 root root 238 Mar 22 21:36 .

dr-xr-xr-x. 18 root root 256 Feb 27 08:31 ..

-rw-------. 1 root root 1420 Jan 26 09:23 anaconda-ks.cfg

-rw-------. 1 root root 27003 Mar 21 22:36 .bash_history

-rw-r--r--. 1 root root 18 Dec 29 2013 .bash_logout

-rw-r--r--. 1 root root 176 Dec 29 2013 .bash_profile

-rw-r--r--. 1 root root 176 Dec 29 2013 .bashrc

-rw-r--r--. 1 root root 100 Dec 29 2013 .cshrc

-rw------- 1 root root 716 Mar 22 21:36 .mysql_history

drwxr----- 3 root root 19 Feb 27 20:16 .pki

drwxr-xr-x 2 root root 6 Mar 5 08:43 practice

-rw------- 1 root root 1024 Mar 21 20:44 .rnd

drwxr-xr-x. 2 root root 157 Jan 26 10:23 shell

drwx------ 2 root root 29 Mar 19 22:52 .ssh

-rw-r--r--. 1 root root 129 Dec 29 2013 .tcshrc

-rw------- 1 root root 7460 Mar 22 19:52 .viminfo

[[email protected] ~]#

[[email protected] ~]# less .mysql_history

_HiStOrY_V2_

use\040mysql

select\040*\040from\040user;

show\040databases;

use\040mysql;

show\040tables;

desc\040users;

desc\040user;

show\040create\040table\040user\134G

show\040create\040table\040user

show\040create\040table\040user;

show\040create\040table\040user\040show\040create\040table\040user;

show\040create\040table\040user

show\040create\040user;

show\040create\040table\040user;

select\040*from\040user;

show\040create\040table\040user;

show\040create\040table\040user\134G;

use\040user;

show\040databases;

use\040mysql;

show\040tables;

desc\040user;

show\040create\040table\040user;

show\040create\040table\040user\134G;

select\040*\040from\040user;

select\040*\040from\040user\134G;

select\040user();

11.查看当前使用的数据库 select database();

mysql> select database();

+------------+

| database() |

+------------+

| NULL |

+------------+

1 row in set (0.00 sec)

mysql>

//NULL代表为空

mysql> use mysql; //切换到mysql下

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql> select database();

+------------+

| database() |

+------------+

| mysql |

+------------+

1 row in set (0.00 sec)

mysql>

创建库

1.创建库 create database db1;

mysql> create database db1;

Query OK, 1 row affected (0.00 sec)

mysql>

2.查看db1库

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| db1 |

| mysql |

| performance_schema |

| test |

+--------------------+

5 rows in set (0.00 sec)

mysql>

3.切换到db1库下面去

mysql> use db1;

Database changed

mysql>

4.创建表 create table t1(id int(4), name char(40));——>定义 id 和 name ，并用反引好括起来

mysql> create table t1(id int(4), name char(40));

Query OK, 0 rows affected (0.17 sec)

mysql>

5.查看创建的表t1，默认使用的是InnoDB 引擎

mysql> show create table t1\G;

*************************** 1. row ***************************

Table: t1

Create Table: CREATE TABLE `t1` (

`id` int(4) DEFAULT NULL,

`name` char(40) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1

1 row in set (0.12 sec)

ERROR:

No query specified

mysql>

6.在数据库里面取消命令，即在命令的最前面加一个 # 号就不会生效了

7.删除表 drop table t1;

mysql> drop table t1;

Query OK, 0 rows affected (0.08 sec)

mysql>

8.创建t1表

mysql> create table t1(`id` int(4), `name` char(40)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Query OK, 0 rows affected (0.03 sec)

mysql>

9.查看表，会看到变成了utf8

mysql> show create table t1\G;

*************************** 1. row ***************************

Table: t1

Create Table: CREATE TABLE `t1` (

`id` int(4) DEFAULT NULL,

`name` char(40) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=utf8

1 row in set (0.00 sec)

ERROR:

No query specified

mysql>

10.查看当前数据库版本 select version();

mysql> select version();

+-----------+

| version() |

+-----------+

| 5.6.35 |

+-----------+

1 row in set (0.05 sec)

mysql>

11.查看数据库状态 show status; 它会把常用的数据都列出来

mysql> show status;

+-----------------------------------------------+-------------+

| Variable_name | Value |

+-----------------------------------------------+-------------+

| Aborted_clients | 0 |

| Aborted_connects | 10 |

| Binlog_cache_disk_use | 0 |

| Binlog_cache_use | 0 |

| Binlog_stmt_cache_disk_use | 0 |

| Binlog_stmt_cache_use | 0 |

| Bytes_received | 1235 |

| Bytes_sent | 22520 |

| Com_admin_commands | 0 |

| Com_assign_to_keycache | 0 |

| Com_alter_db | 0 |

| Com_alter_db_upgrade | 0 |

…………………………………………//下面省略很多

12.查看各参数

show variables;
show variables like 'max_connect%'; //mysql下 % 为通配符

mysql> show variables like 'max_connect%';

+--------------------+-------+

| Variable_name | Value |

+--------------------+-------+

| max_connect_errors | 100 |

| max_connections | 151 |

+--------------------+-------+

2 rows in set (0.00 sec)

mysql> show variables like 'slow%';

+---------------------+--------------------------------+

| Variable_name | Value |

+---------------------+--------------------------------+

| slow_launch_time | 2 |

| slow_query_log | OFF |

| slow_query_log_file | /data/mysql/tianqi-01-slow.log |

+---------------------+--------------------------------+

3 rows in set (0.00 sec)

mysql>

13.修改参数 set global max_connect_errors=1000; ——>仅在内存中生效

mysql> set global max_connect_errors=1000;

Query OK, 0 rows affected (0.04 sec)

mysql> show variables like 'max_connect%';

+--------------------+-------+

| Variable_name | Value |

+--------------------+-------+

| max_connect_errors | 1000 |

| max_connections | 151 |

+--------------------+-------+

2 rows in set (0.00 sec)

mysql>

若想重启依然生效，那需要修改配置文件/etc/my.cnf
在[mysqld]里面定义

14.查看队列

show processlist; //查看库的状况，比如，那些用户在连，做了些什么操作，是否锁表

mysql> show processlist;

+----+------+-----------+------+---------+------+-------+------------------+

+----+------+-----------+------+---------+------+-------+------------------+

+----+------+-----------+------+---------+------+-------+------------------+

1 row in set (0.00 sec)

mysql> show full processlist;

+----+------+-----------+------+---------+------+-------+-----------------------+

+----+------+-----------+------+---------+------+-------+-----------------------+

+----+------+-----------+------+---------+------+-------+-----------------------+

1 row in set (0.00 sec)

mysql>

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