Solution for mysql to accidentally delete the root user or forget the root password

I accidentally deleted the root user of mysql and found a lot of solutions on the Internet. Due to the large number of mysql databases and the trouble of reinstalling them, I have been trying various methods, finally, it succeeded. The procedure is as follows:

1. Stop the mysqld process first.

# Killall mysqld

Enter mysql without loading grant_tables

# Mysqld_safe -- skip-grant-tables &

Go to mysql
#/Usr/local/mysql/bin/mysql

Mysql> use mysql

Database changed

Mysql> select * from user;

Empty set (0.00 sec)

Mysql> insert into user set user = 'root', ssl_cipher = '', x509_issuer ='', x509_subject = '';

(Add a table as the root user)

Query OK, 1 row affected, 3 warnings (0.00 sec)
(A field such as ssl_cipher has no default value., Ssl_cipher = ''; if any of its fields is prompted, add them one by one.
)

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 ';

(The root user permission is modified here)

Mysql> quit;

2. Start mysql normally with the permission

# Service mysqld start

3. Log On with the root user (if phpadmin is available, log on with the root empty password and then change the password or permission)

# Mysql-u root-p

Mysql> update user set password = password ('20140901 ')
 Where user = 'root ';

Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0

Mysql> flush privileges;

Mysql> quit

Mysql

# Mysql-u root
ERROR 1045 (28000): Access denied for user 'root' @ 'localhost' (using password: NO)

Use the password to enter mysql

# Mysql-u root-p 123456
Welcome to the MySQL monitor. Commands end with; or/g.
Your MySQL connection id is 25 to server version: 4.1.20

Type 'help; 'or'/H' for help. type'/C' to clear the buffer.

Mysql>

I have not personally verified this problem and I have reinstalled it before I found this article. If you have this problem, try it.