54:mysql修改密码|链接mysql|mysql经常使用命令

时间 2019-11-07

标签 mysql 修改密码链接经常使用命令栏目 MySQL 繁體版

原文原文链接

一、mysql修改密码：html

root用户时mysql的超级管理员,默认mysql的密码是空的,直接能够链接上去的,不过这样不安全；mysql

注释：为了方便的使用mysql,须要把mysql加入到环境变量里； #后续本身输入mysql能够进入到mysql下；linux

(1):启动mysql后,使用mysql -uroot命令,会提示mysql命令不存在,这是由于安装的mysql是在/usr/local/mysql/bin/mysql,而这个目录不在环境变量PATH里面,因此会报错,若想要这个命令直接运行,须要把PATH作一个更改；web

[root@localhost_001 vhost]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
[root@localhost_001 vhost]# export PATH=$PATH:/usr/local/mysql/bin

注释：export声明的变量临时生效,会在重启后失效；sql

注释：若想变量永久生效,建议PATH=$PATH:/usr/local/mysql/bin写入到/etc/profile文件里,而后执行 source /etc/profile；数据库

(2):进入mysql, 使用mysql -uroot 就能够进入mysql,退出mysql使用quit或者exit便可；vim

[root@localhost_001 vhost]# mysql -uroot
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.6.39 MySQL Community Server (GPL)

Copyright (c) 2000, 2018, 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

注释：登陆mysql通常使用 mysql -uroot -p (-p表示指定密码)：密码为空时,直接回车也可进入到mysql；安全

(3):设置mysql的登陆密码；(当前mysql没有密码的状况下设置)； mysqladminbash

[root@localhost_001 ~]# mysqladmin -uroot password 'nihao123!'
Warning: Using a password on the command line interface can be insecure.

注释：提示是警告信息,是说你如今的命令在当前的命令行显示出来了,这样不太安全；socket

登陆mysql；

[root@localhost_001 ~]# mysqladmin -uroot password 'nihao123!'       #要求密码登陆；
Warning: Using a password on the command line interface can be insecure.
[root@localhost_001 ~]# mysql -uroot 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
[root@localhost_001 ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 12
Server version: 5.6.39 MySQL Community Server (GPL)

Copyright (c) 2000, 2018, 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>

注释：当设置的密码以后,再次登陆时会提示输入密码才能登陆,如上图；

(4):在知道mysql的密码的状况下,去修改mysql的密码；

[root@localhost_001 ~]# mysqladmin -uroot -p'nihao123!' password 'nihao123@'
Warning: Using a password on the command line interface can be insecure.

注释：如上格式： mysqladmin -uroot -p'旧密码' password '新密码'

注释：在明文指定密码的时候,密码能够加单引号,也能够不加单引号,建议加上单引号,防止密码有特殊字符的存在(如果不加单引号,而密码中又有中文字符,则会不识别)；

注释：指定新密码登陆,固然也能够不明文登陆, -p回车输入密码也能够；

[root@localhost_001 ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 20
Server version: 5.6.39 MySQL Community Server (GPL)

Copyright (c) 2000, 2018, 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):在忘记mysql密码的时候修改mysql的密码；

首先要去mysql的配置文件/etc/my.cnf里加入skip-grant；而后重启mysql服务,再次进入mysql则不须要密码；

skip-grant 表示忽略受权,也就是登陆mysql的时候不须要输入密码,能够直接登陆；

[root@localhost_001 ~]# vim  /etc/my.cnf
[mysqld]
skip-grant
datadir=/data/mysql
socket=/tmp/mysql.sock
[root@localhost_001 ~]# service mysqld restart
Shutting down MySQL.. SUCCESS! 
Starting MySQL. SUCCESS!

(1):登陆mysql,在登陆mysql后,还须要更改一个user表(这个表里存放的用户名和密码),这个表在mysql库里面；(进入到这个库)

[root@localhost_001 ~]# mysql -uroot        #进入mysql;
Welcome to the MySQL monitor.  Commands end with ; or \g.
mysql> use mysql;                           #切换mysql库;
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>

(2):查看user表和password表相关信息；

select * from user; -----> 查看user表,会看到不少的乱码信息,这里保存的mysql的用户名和密码等信息；

select password from user user='root'; 针对root用户查看password表；

mysql> select password from user where user='root';
+-------------------------------------------+
| password                                  |
+-------------------------------------------+
| *FA22FC2D09A3E4C4F63AAE8F4AE18DD2F3E7E695 |
|                                           |
|                                           |
|                                           |
+-------------------------------------------+
4 rows in set (0.00 sec)

(3):更改mysql的密码；

update user set password=('111111') where user='root';

密码字段函数 | 用于加密密码 |为条件语句

mysql> update user set password=password('111111') where user='root';
Query OK, 4 rows affected (0.08 sec)
Rows matched: 4  Changed: 4  Warnings: 0

注释：提示说4行则表示密码更改完成；可按以下方式验证；

先去my.cnf的配置文件了注释掉skip-grant(受权登陆)；(若是不删除,那么全部的用户都不须要输入密码就能够登陆,这样不安全)；

重启mysql服务; service msyqld restart

而后用新密码登陆验证； mysql -uroot -p111111

这样即成功修改可mysql的密码；

链接mysql的方式, 本地链接 or 远程链接；

本地链接：即便没有使用-S来指定socket,默认也是使用/tmp/mysql.sock链接；

mysql -uroot -p11111 <==========> mysql -uroot -p11111 -S/tmp/mysql.sock

[root@localhost_001 ~]# mysql -uroot -p111111
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> quit
Bye
[root@localhost_001 ~]# mysql -uroot -p111111 -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.
mysql>

注释：socket方式只能使用本地链接使用；

远程链接： mysql -uroot -p密码 -h[远端mysql主机IP地址] -P[远端mysql端口号] #无前后顺序；

[root@localhost_001 ~]# mysql  -uroot  -p111111 -h127.0.0.1 -P3306
Warning: Using a password on the command line interface can be insecure.
mysql> exit
Bye

假设咱们从A机器(192.168.149.130)链接B机器(192.168.149.129)的mysql数据库；

[root@localhost_002 ~]# mysql -h192.168.149.129 -P3306 -p111111
Warning: Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'root'@'192.168.149.130' (using password: YES)

注释：如上链接时提示错误；由于mysql默认是只容许127.0.0.1和localhost登陆,因此须要添加容许192.168.149.130受权登陆；

在B机器(192.168.149.129)执行以下；

mysql> grant all privileges on *.* TO 'root'@'192.168.149.130' identified by 'nihao123!' with grant option;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;                #刷新权限；
Query OK, 0 rows affected (0.00 sec)

在A机器(192.168.149.130)远程链接便可；

[root@localhost_002 ~]# mysql -h192.168.149.129 -P3306 -pnihao123!
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>

注释：在B机器(192.168.149.129)查看受权的用户；

mysql> select host from user where user='root';
+-----------------+
| host            |
+-----------------+
| 127.0.0.1       |   
| 192.168.149.130 |
| ::1             |
| localhost       |
| localhost\_001  |
+-----------------+
6 rows in set (0.00 sec)

注释：目前的只容许本地和远程主机130登陆,其他主机都拒绝；

注释：通常为了安全性,mysql主机是本地登陆的；

注释：固然若是想让全部用户都链接mysql,能够以下设置；

mysql> grant all privileges on *.* TO 'root'@'%' identified by 'nihao123!' with grant option;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;                #刷新权限；
Query OK, 0 rows affected (0.00 sec)

1：链接mysql后远程执行命令后退出； mysql -uroot -p111111 -e "show databases;"

[root@localhost_001 ~]# mysql -uroot -p111111 -e "show databases;"
Warning: Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+

远程链接执行命令； mysql -h192.168.149.129 -uroot -pnihao123! -P3306 -e “show databases;”

[root@localhost_002 ~]# mysql -h192.168.149.129 -uroot -pnihao123! -P3306 -e "show databases;"
Warning: Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+

mysql经常使用命令；

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();
建立库 create database db1;
建立表 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;

1:建立库； create databases db1;

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

2:查看有哪些库； show databases;

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

3:切换库； use mysql;

mysql> use db1;
Database changed

4:建立表； create tables 后面加字段；

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

5:查看表里的字段; show create table t1\G; desc user; -------> 查看user表有哪些字段；

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 (0.00 sec)

ERROR: 
No query specified
mysql> desc t1\G
*************************** 1. row ***************************
  Field: id
   Type: int(4)
   Null: YES
    Key: 
Default: NULL
  Extra: 
*************************** 2. row ***************************
  Field: name
   Type: char(40)
   Null: YES
    Key: 
Default: NULL
  Extra: 
2 rows in set (0.00 sec)

注释：在命令前面加#号则表示取消这个命令；

删除一个表； drop table t1;

mysql> drop table t1;
Query OK, 0 rows affected (0.03 sec)

从新建立一个表,并指定字符集为utf-8；

mysql> create table t1(`id` int(4), `name` char(40)) ENGINE=InnoDB DEFAULT  CHARSET=utf8;
Query OK, 0 rows affected (0.02 sec)

再次查看会发现字符集变成了utf-8；

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

6:查看当当前所在库； select database();

mysql> select database();
+------------+
| database() |
+------------+
| db1        |
+------------+
1 row in set (0.00 sec)

7:查看当前登陆数据库的用户； select user();

mysql> select user();
+--------------------+
| user()             |
+--------------------+
| root@localhost_001 |
+--------------------+
1 row in set (0.00 sec)

8:查看当前数据库的版本； select version();

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.39    |
+-----------+
1 row in set (0.00 sec)

show status; 列出mysql的数据库状态,会把经常使用数据都列出来；

9:查看mysql的各个参数(在/etc/my.cnf定义的参数)；

查看mysql定义各个参数： show variables;

查看指定的参数,用like； show variables like 'max_connect%';

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

10:修改参数,不过仅在内存中生效； set global max_connect_errors=1000;

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

注释：如果想从新后生效,能够修改/etc/my.cnf配置文件；

11:查看队列； show processlist; 用来查看有哪些用户在连mysql,在作什么操做,是否有锁表；

mysql> show processlist;
+----+------+---------------------+------+---------+------+-------+------------------+
| Id | User | Host                | db   | Command | Time | State | Info             |
+----+------+---------------------+------+---------+------+-------+------------------+
|  6 | root | localhost_001:55484 | db1  | Query   |    0 | init  | show processlist |
+----+------+---------------------+------+---------+------+-------+------------------+
1 row in set (0.00 sec)

12： show full processlist; #同查看队列命令,不会最后一列会较详细的显示出来；

mysql> show full processlist;
+----+------+---------------------+------+---------+------+-------+-----------------------+
| Id | User | Host                | db   | Command | Time | State | Info                  |
+----+------+---------------------+------+---------+------+-------+-----------------------+
|  6 | root | localhost_001:55484 | db1  | Query   |    0 | init  | show full processlist |
+----+------+---------------------+------+---------+------+-------+-----------------------+
1 row in set (0.00 sec)

注释：

mysql5.7 root密码更改 http://www.apelearn.com/bbs/thread-7289-1-1.html myisam 和innodb引擎对比 http://www.pureweber.com/article/myisam-vs-innodb/ 知乎上的答案 https://www.zhihu.com/question/20596402 mysql 配置详解：https://www.jb51.net/article/48082.htm mysql调优： http://www.aminglinux.com/bbs/thread-5758-1-1.html 同窗分享的亲身mysql调优经历： http://www.apelearn.com/bbs/thread-11281-1-1.html