MySQL更改root密码、连接MySQL、MySQL常用命令介绍

更改MySQL数据库root密码

1. 首次进入数据库是不用密码的，如下所示：

[root@gary-tao ~]# /usr/local/mysql/bin/mysql -uroot //使用绝对路径进入mysql
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)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> 

说明：退出时直接输入quit或者exit即可，上面我们是使用绝对路径进入mysql的,这样很不方便，由于/usr/local/mysql/bin不在PATH这个环境变量里，所以不能直接使用mysql这条命令，那我们就需要把它加入到环境变量PATH中，方法如下：

[root@gary-tao ~]# ls /usr/local/mysql/bin/mysql
/usr/local/mysql/bin/mysql
[root@gary-tao ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
[root@gary-tao ~]# export PATH=$PATH:/usr/local/mysql/bin/  //加入PATH,但重启后会失效
[root@gary-tao ~]# mysql -uroot  //-u是指定要登录的用户，后面有无空格均可。
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)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> 
[root@gary-tao ~]# vi /etc/profile  //添加后重启会开机加载

把以下命令增加到最后一行：

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

[root@gary-tao ~]# source /etc/profile  //即刻生效

2.设置mysql的root密码

[root@gary-tao ~]# mysqladmin -uroot password ‘szyino-123‘  //设置密码
Warning: Using a password on the command line interface can be insecure.

警告信息：在命令行下面暴露了密码，这样不安全。

3.使用密码登录mysql

[root@gary-tao ~]# mysql -uroot  //报错，提示需要密码登录 
ERROR 1045 (28000): Access denied for user ‘root‘@‘localhost‘ (using password: NO)
[root@gary-tao ~]# mysql -uroot -p //交互的方式输入密码登录
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> exit
Bye
[root@gary-tao ~]# mysql -uroot -p‘szyino-123‘ //直接-p后面跟密码登录，-P后面不需要有空格。
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 6
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> 

4.更改mysql的root密码

[root@gary-tao ~]# mysqladmin -uroot -p‘szyino-123‘ password ‘Szyino-123‘  //更改密码
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao ~]# mysql -uroot -p‘Szyino-123‘ //使用新密码登录
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 8
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> 

5.重置密码

• 更改配置文件

[root@gary-tao ~]# vim /etc/my.cnf

增加如下内容：

skip-grant

如图：

• 重启mysql

[root@gary-tao ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL.. SUCCESS! 
[root@gary-tao ~]# 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)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> 

• 进入密码表更改密码

mysql> use mysql;  //用户名密码存在user表里，而user表存在mysql这个库里，进入mysql，记得加分号
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 * from user;  //查看user表
mysql> select password from user where user=‘root‘ ; //查询语句查询密码表。加密的字符串是password这个函数生成
+-------------------------------------------+
| password                                  |
+-------------------------------------------+
| *EBBC0E0C643D4DC86D226068E9C5A6693BB555A6 |
|                                           |
|                                           |
|                                           |
+-------------------------------------------+
4 rows in set (0.01 sec)

mysql> update user set password=password(‘szyino-123‘) where user=‘root‘;  //更改密码命令
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4  Changed: 4  Warnings: 0

• 把vi /etc/my.cnf增加的skip-grant去掉，否则所有的用户登录都不需要密码，不安全。

[root@gary-tao ~]# vi /etc/my.cnf //去掉skip-grant
[root@gary-tao ~]# /etc/init.d/mysqld restart  //重启mysql
Shutting down MySQL.. SUCCESS! 
Starting MySQL. SUCCESS! 
[root@gary-tao ~]# mysql -uroot -pszyino-123 //使用新密码测试登录mysql
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)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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

连接mysql

1.连接本机数据库

[root@gary-tao ~]# mysql -uroot -p‘123456‘

2.远程连接登录mysql，A机器连接B服务器的mysql，就需要加上IP和端口,如下：

[root@gary-tao ~]# mysql -uroot -pszyino-123 -h127.0.0.1 -P3306 //-h用来指定远程主机的IP -P指定端口 
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 4
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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.使用sock远程连接

[root@gary-tao ~]# mysql -uroot -pszyino-123 -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 6
Server version: 5.6.35 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

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> 

说明：mysql我们本机不止监听了3306也监听了sock，所以就可以使用sock登陆，但这个时候不是使用TCP/IP连接，是使用sock,只适合在本机。

4. 连接mysql后，把数据库表列出来，这种情况只适用在shell脚本里。

[root@gary-tao ~]# mysql -uroot -pszyino-123 -e "show databases"
Warning: Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+

mysql常用命令

在日常工作中，难免会遇到一些与Mysql相关的操作，比如建库、建表、查询MySQL状态等，掌握最基本的操作。

注意：使用mysql命令的结尾处都需要加一个分号。

1.查询当前库

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.00 sec)

2.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

3.查询库的表

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 (0.00 sec)

4.查看表里的字段

mysql> desc user;
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field                  | Type                              | Null | Key | Default               | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Host                   | char(60)                          | NO   | PRI |                       |       |
| User                   | char(16)                          | NO   | PRI |                       |       |
| Password               | char(41)                          | NO   |     |                       |       |
| 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                     |       |
| ssl_type               | enum(‘‘,‘ANY‘,‘X509‘,‘SPECIFIED‘) | NO   |     |                       |       |
| ssl_cipher             | blob                              | NO   |     | NULL                  |       |
| x509_issuer            | blob                              | NO   |     | NULL                  |       |
| x509_subject           | blob                              | NO   |     | NULL                  |       |
| 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                     |       |
| plugin                 | char(64)                          | YES  |     | mysql_native_password |       |
| authentication_string  | text                              | YES  |     | NULL                  |       |
| password_expired       | enum(‘N‘,‘Y‘)                     | NO   |     | N                     |       |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
43 rows in set (0.01 sec)

5.查看建表语句

mysql> show create table user\G;

6.查看当前用户

mysql> select user();
+----------------+
| user()         |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)

7.查看当前使用的数据库

mysql> select database();
+------------+
| database() |
+------------+
| mysql      |
+------------+
1 row in set (0.00 sec)

8.创建库

mysql> create database db1;  //创建库
Query OK, 1 row affected (0.00 sec)

mysql> show databases;    //查看库
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db1                |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.00 sec)

9.创建表

mysql> use db1; create table t1(`id` int(4), `name` char(40));
Database changed
Query OK, 0 rows affected (0.03 sec)

mysql> show create table t1\G;  //查看创建的表
*************************** 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 (0.01 sec)

ERROR: 
No query specified
mysql> drop table t1;  //删除表
Query OK, 0 rows affected (0.01 sec)

mysql> use db1; create table t1(`id` int(4), `name` char(40)) ENGINE=InnoDB DEFAULT CHARSET=utf8;  //创建表时指定CHARSET=utf8
Database changed
Query OK, 0 rows affected (0.02 sec)

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

9.查看当前数据库版本

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.35    |
+-----------+
1 row in set (0.00 sec)

10.查看数据库状态

mysql> show status;

11.查看各参数

mysql> show variables; 
mysql> show variables like ‘max_connect%‘;
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| max_connect_errors | 100   |
| max_connections    | 151   |
+--------------------+-------+
2 rows in set (0.00 sec)

12.修改参数

mysql> set global max_connect_errors=1000;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like ‘max_connect%‘;
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| max_connect_errors | 1000  |
| max_connections    | 151   |
+--------------------+-------+
2 rows in set (0.00 sec)

13.查看数据库队列

mysql> show processlist; 
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
| 11 | root | localhost | db1  | Query   |    0 | init  | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
1 row in set (0.01 sec)

mysql> show full processlist;
+----+------+-----------+------+---------+------+-------+-----------------------+
| Id | User | Host      | db   | Command | Time | State | Info                  |
+----+------+-----------+------+---------+------+-------+-----------------------+
| 11 | root | localhost | db1  | Query   |    0 | init  | show full processlist |
+----+------+-----------+------+---------+------+-------+-----------------------+
1 row in set (0.00 sec)