mysql更改root密码,连接mysql，常用操作

Posted 2020-11-19

mysql设置更改root密码

• export PATH=$PATH:/usr/local/mysql/bin/ 把mysql加入环境变量可以直接使用mysql命令，永久生效要把这条命令放到/etc/profile,并source /etc/profile
• 设置密码

  [[email protected] ~]# mysqladmin -uroot password ‘s5381561‘
  Warning: Using a password on the command line interface can be insecure.
  [[email protected] ~]# mysql -uroot 
  ERROR 1045 (28000): Access denied for user ‘root‘@‘localhost‘ (using password: NO)

• 更改密码

  [[email protected] ~]# mysqladmin -uroot -p‘s5381561‘ password ‘123456‘
  Warning: Using a password on the command line interface can be insecure.
  [[email protected] ~]# mysql -uroot -p‘123456‘
  mysql> 

• 忘记密码时，进行密码更改
  • 改配置文件

    [[email protected] ~]# vim /etc/my.cnf
    [mysqld]
    skip-grant  #忽略授权
    [[email protected] ~]# vim /etc/my.cnf
    [[email protected] ~]# /etc/init.d/mysqld restart
    Shutting down MySQL.. SUCCESS! 
    Starting MySQL.. SUCCESS! 
    [[email protected] ~]# mysql -uroot
    Welcome to the MySQL monitor.  Commands end with ; or g.

  • 更改密码

    [[email protected] ~]# mysql -uroot
    Welcome to the MySQL monitor.  Commands end with ; or g.
    mysql> use mysql;
    #切换mysql库
    Database changed
    mysql> select * from userG;
    #查看用户的表信息，该表中存放的是用户相关信息（密码、授权…）
    #G选项的作用是使输出信息有序显示，不加该选项，显示内容会很乱  
    mysql> select password from user;
    #查看用户密码，显示结果Wie加密字符串！  
    mysql> update user set password=password(‘1234567‘) where user=‘root‘;
    Query OK, 4 rows affected (0.11 sec)
    Rows matched: 4  Changed: 4  Warnings: 0
    #将密码更改为‘1234567’
    mysql> quit
    Bye

  • 恢复配置文件并重启

    [[email protected] ~]# vim /etc/my.cnf
    [[email protected] ~]# /etc/init.d/mysqld restart
    Shutting down MySQL.. SUCCESS! 
    Starting MySQL. SUCCESS! 
    [[email protected] ~]# mysql -uroot -p1234567
    Warning: Using a password on the command line interface can be insecure.

连接mysql

• 远程连接

  [[email protected] ~]# mysql -uroot -p1234567 -h127.0.0.1 -P3306
  Warning: Using a password on the command line interface can be insecure.

• 本地连接

  [[email protected] ~]# mysql -uroot -p1234567 -S/tmp/mysql.sock
  Warning: Using a password on the command line interface can be insecure.

• 显示所有数据库,该方法使用于shell脚本中

  [[email protected] ~]# mysql -uroot -p‘1234567‘ -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

• 查看库信息
  • show databases; | 查询所有数据库
  • use db_name; | 切换库
  • show tables; | 查看库中的表
  • desc tb_name | 查看表里的字段
  • show create table tb_nameG; | 查看建表语句
  • select user(); | 查看当前用户
  • select database(); | 查看当前使用的数据库
  • select * from userG; | 查看所有用户
• 编辑库
  • create database db_name； | 创建库
  • use db_name;create table tb_name | 在某库下创建表
  • select version(); | 查看当前数据库版本
  • show status; | 查看数据库状态
  • show variables; | 查看所有参数
  • show variables like ‘max_connet%‘ | 查看某参数,%为通配符
  • set global max_connect_errors=100; | 修改某参数 可以在my.cnf里永久修改
  • show processlist; | 查看mysql进程队列
  • show full processlist | 查看队列详细信息
  • drop database db_name | 删除库
• 代码

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

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> show tables;
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| columns_priv              |
| db                        |
| event                     |
| func                      |
| time_zone                 |
| time_zone_leap_second     |
+---------------------------+
28 rows in set (0.00 sec)

mysql> desc time_zone;
+------------------+------------------+------+-----+---------+----------------+
| Field            | Type             | Null | Key | Default | Extra          |
+------------------+------------------+------+-----+---------+----------------+
| Time_zone_id     | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| Use_leap_seconds | enum(‘Y‘,‘N‘)    | NO   |     | N       |                |
+------------------+------------------+------+-----+---------+----------------+
2 rows in set (0.11 sec)

mysql> show create table time_zoneG;
#G=grep筛选文字内容，规律显示出来
*************************** 1. row ***************************
       Table: time_zone
Create Table: CREATE TABLE `time_zone` (
  `Time_zone_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `Use_leap_seconds` enum(‘Y‘,‘N‘) NOT NULL DEFAULT ‘N‘,
  PRIMARY KEY (`Time_zone_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT=‘Time zones‘
1 row in set (0.03 sec)

ERROR: 
No query specified

mysql> select user();
+----------------+
| user()         |
+----------------+
| [email protected] |
+----------------+
1 row in set (0.07 sec)

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

mysql> select * from userG;
创建库：
mysql> create database db1;
Query OK, 1 row affected (0.02 sec)

创建表：
mysql> use db1;  
#先切换到指定库下
Database changed
mysql> create table t1(`id` int(4),`name` char(40)) ENGINE=InnoDB DEFAULT CHARSET=utf8;
#括号中是定义字段及字段格式，使用反引号引起来
Query OK, 0 rows affected (1.51 sec)

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.35    |
+-----------+
1 row in set (0.06 sec)

mysql> show status;
+-----------------------------------------------+-------------+
| Variable_name                                 | Value       |
+-----------------------------------------------+-------------+
| Aborted_clients                               | 0           |
| Aborted_connects                              | 0           |
+-----------------------------------------------+-------------+

mysql> show variablesG;

mysql> show variables like ‘max_connect%‘G;
#like表示匹配；%是通配符

更改参数：
mysql> set global max_connect_errors=110;
Query OK, 0 rows affected (0.04 sec)
#在此只是临时更改，如果要永久更改，需要编辑配置文件

查看队列：
mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
|  5 | root | localhost | db1  | Query   |    0 | init  | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
1 row in set (0.01 sec)

mysql> drop table t1;
Query OK, 0 rows affected (0.32 sec)

mysql> drop database db1;
Query OK, 0 rows affected (0.10 sec)

扩展

• mysql5.7 root密码更改
• myisam 和innodb引擎对比
• mysql 配置详解：
• mysql调优：
• 同学分享的亲身mysql调优经历：