MYSQL Login Error: mysqladmin: connect to server at ‘localhost’ failed

1.mysql登录错误

mysqladmin: connect to server at ‘localhost’ failed error: ‘Access denied for user ‘root’@’localhost’ (using password: NO)’

ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: YES)

Unable to change password

Take service mysqld stop with 

Type mysql -uroot -p and enter
Enter the original password

> use mysql;

> update user set password=PASSWORD("long.com") where user="root";
> change password to long.com

> flush privileges; #update privileges

> quit quit

service mysqld restart
mysql -uroot -p new password enter

Second, forget the login password of local root

Solution process:

1. Edit/etc/my.cnf

Add a line in the [mysqld] configuration section

skip-grant-tables

2. Restart MySQL after saving

[root@web02 etc]# service mysqld restart
Shutting down MySQL.                                       [  OK  ]
Starting MySQL.                                                   [  OK  ]

3. Log in to the database and reset the root password

[root@web02 ~]# mysql -uroot -p mysql
Enter password:

Enter directly

Execute the following statement

mysql> update user set password=password("mysql") where user='root';
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4  Changed: 4  Warnings: 0

If you execute the last one, the error is as follows:
mysql> update user set password=password("123") where user='root';
ERROR 1054 (42S22): Unknown column 'password' in 'field list'

#The reason for the error is that the password field is no longer available in the mysql database under version 5.7, and the password field has been changed to authentication_string

Then use:
mysql> update mysql.user set authentication_string=password('123') where user='root';
Query OK, 1 row affected, 1 warning (0.02 sec)
Rows matched: 1  Changed: 1  Warnings: 1


mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
 

4. Delete the “skip grant tables” line added in the/etc/my.cnf file and restart mysql

You can log in normally with the new password