MySQL mistakenly deleted the root account and failed to log in

Processing mysql When logging in remotely , False deletion mysql.user In the table root Record , Unable to log in after exiting

terms of settlement ：
1、vim /etc/my.cnf
increase ：
[mysqld]
skip-grant-tables

2、 restart mysql
systemctl restart mysqld

3、 Remedial treatment ：

update user set Host='localhost',
select_priv='y',
 insert_priv='y',
update_priv='y',
Alter_priv='y',
delete_priv='y',
create_priv='y',
drop_priv='y',
reload_priv='y',
shutdown_priv='y',
Process_priv='y',
file_priv='y',
grant_priv='y',
References_priv='y',
index_priv='y',
create_user_priv='y',
show_db_priv='y',
super_priv='y',
create_tmp_table_priv='y',
Lock_tables_priv='y',
execute_priv='y',
repl_slave_priv='y',
repl_client_priv='y',
create_view_priv='y',
show_view_priv='y',
create_routine_priv='y',
alter_routine_priv='y',
create_user_priv='y' 
where user='root';

flush privileges;

4、 restart mysql
systemctl restart mysqld

5、MySQL5.7 Version password setting

MySQL The password you set must contain at least one uppercase letter 、 A small letter 、 A special symbol 、 A number ,
Password length must be at least 8 Characters