# 删除一个用户(::1 是本机 ipv6 地址)
mysql> drop user root@‘::1‘;
Query OK, 0 rows affected (0.00 sec)
# 删除所有用户
mysql> delete from mysql.user where 1=1;
Query OK, 4 rows affected (0.00 sec)
# 删除用户以后还是可以登陆,但是不要重启,重启就会出现故障报错
[root@db02 scripts]# systemctl stop mysqld
[root@db02 scripts]# mysqld_safe --skip-grant-tables --skip-networking &
insert into mysql.user values (‘localhost‘,‘root‘,PASSWORD(‘123‘),
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘Y‘,
‘‘,
‘‘,
‘‘,
‘‘,0,0,0,0,‘mysql_native_password‘,‘‘,‘N‘);
[root@db02 scripts]# mysqladmin shutdown
200709 16:27:19 mysqld_safe mysqld from pid file /usr/local/mysql/data/db02.pid ended
[1]+ Done mysqld_safe --skip-grant-tables --skip-networking
[root@db02 scripts]# systemctl start mysqld
[root@db02 scripts]# systemctl stop mysqld
[root@db02 scripts]# mysqld_safe --skip-grant-tables --skip-networking &
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> grant all on *.* to root@‘localhost‘ identified by ‘123‘ with grant option;
Query OK, 0 rows affected (0.00 sec)
[root@db02 scripts]# mysqladmin -uroot -p123 shutdown
[root@db02 scripts]# systemctl start mysqld
原文:https://www.cnblogs.com/zzzwqh/p/13275636.html