一、修改密码方法：
方法1：
代码语言：javascript复制set global validate_password_policy=LOW;
alter user 'root'@'localhost' identified by 'test';方法2：
代码语言：javascript复制set global validate_password_policy=LOW;
set password for 'root'@'localhost'=password('test');方法3：
代码语言：javascript复制set global validate_password_policy=LOW;
update mysql.user set authentication_string=password('test') where user='root' and Host = 'localhost';刷新权限
代码语言：javascript复制flush privileges;查询用户，主机名，加密字符串
代码语言：javascript复制select user,host,authentication_string from mysql.user;
二、用户授权
代码语言：javascript复制create database db_test;
create user 'demo'@'%' identified by 'test';
grant select,insert,delete,update on db_test.* to 'demo'@'%' ;
select user,host,authentication_string from mysql.user;
flush prvileges;三、数据库开启主从后，从库为了防止别人误修改文件，开启只读模式，导致密码不能正确修改
代码语言：javascript复制mysql> update mysql.user set authentication_string=password('qaws213gt') where user='itdemo' and Host = '%';
ERROR 1290 (HY000): The MySQL server is running with the --super-read-only option so it cannot execute this statement
mysql> set global read_only=0;
Query OK, 0 rows affected (0.00 sec)
查询是否开启只读模式 read_only 为1 ，开启
代码语言：javascript复制mysql> select @@read_only;
-------------
| @@read_only |
-------------
| 1 |
-------------
1 row in set (0.00 sec)解决方法：关闭只读模式
代码语言：javascript复制mysql> set global read_only=0;
Query OK, 0 rows affected (0.00 sec)
mysql> update mysql.user set authentication_string=password('demo') where user='itdemo' and Host = '%';
Query OK, 1 row affected, 1 warning (0.04 sec)
Rows matched: 1 Changed: 1 Warnings: 1
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
