1修改密码

`方法1： SET PASSWORD

首先登录mysql控制台
格式：mysql> set password for 用户名@localhost = password('新密码');
例子：mysql> set password for root@localhost = password('123');
mysql> DROP USER 'jack'@'localhost';
mysql> DROP USER ''@'localhost'; #删除空用户

`方法2：mysqladmin
格式：mysqladmin -u用户名 -p旧密码 password 新密码
例子：mysqladmin -uroot -p123456 password 123

mysql> update user set password=password('新密码') where user='root'; ??

1.1 mysql5.6密码设置

set password=password('123123') 初始密码设置
set password for 'user'@'host'=password('123123')   忘记root密码重置
update mysql.user set password=password('123123') where user='' and host=''

1.2 mysql5.7密码设置

set password=password('123123')初始密码设置
alter user root@'localhost' identified by '123123'
set password for 'root'@'localhost'=password('123123');
update mysql.user set authentication_string=password('321321') where user='root' and host='localhost';

1.3 mysql8.0密码设置

alter user root@'localhost' identified by '123123';

mysql5.6和mysql5.7支持自动创建用户,授权和撤销权限之类与8.0相同
grant all privileges on databasename.tablename to 'username'@'host' identified by 'password';

mysql8.0建用户和授权分开了
grant 不再支持自动创建用户了，不支持改密码,授权之前，必须要提前创建用户。
创建用户
create user 'username'@'host' identified by 'password';
给用户授权
grant all privileges on databasename.tablename to 'username'@'host';关键字privileges可以省略
查看用户权限
show grants for 'username'@'host';
撤销用户权限
revoke all privileges on databasename.tablename from 'username'@'host';
删除用户
drop user 'username'@'host';

2 mysql同步账户密码修改步骤

master执行

mysql>select user,host,password from mysql.user ; #查看用户清单
mysql>set password for 'repl'@'%'= password('repl_123456');# ‘%’根据实际填写  
mysql>select user,password,host from mysql.user where user='repl';

slave执行

mysql>show slave status\G;#执行完会发现同步状态已中断
mysql>stop slave ;
mysql>change master to master_user='repl',  master_password='repl_123456'; 
mysql>SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1; #跳过一个事务
mysql>start slave;
mysql>show slave status\G;#检查主备状态是否正常