MySQL & #39; root & #39; @ & #39; localhost & #39; login failure, mysqllocalhost

MySQL 'root' @ 'localhost' cannot be logged on, mysqllocalhost

This morning, my colleague said that the MySQL root Account could not be logged on. I tried it.
# Mysql-u root-p
Prompt "Access denied for user 'root' @ 'localhost' (using password: YES )"

Because a colleague resigned after the year, my first response was: Who modified the root password? Reset the password Based on the root password you forgot:
#/Etc/init. d/mysql stop
# Mysqld_safe-skip-grant-tables &
# Mysql-uroot-p
Mysql> update mysql. user set password = password ('mypassword') where user = 'root ';
Mysql> flush privileges;
Mysql> quit

You still cannot log on with the new password. The prompt is the same as above. Log on to another non-root account and check the user table:
Mysql> select user, host from user;
+ ---- + --- +
| User | host |
+ ---- + --- +
| Root | 127.0.0.1 |
| Night | % |
+ ---- + --- +

Suspect that the default localhost is not mapped to 127.0.0.1? Try # mysql-u root-p xxxx-h 127.0.0.1. you can log on.
Previously, the Database Configuration personnel did not grant 'root' @ 'localhost' and 'root' @ 'IP' authorization.
Grant all privileges on.To 'root' @ 'localhost' identified by 'mypassword' with grant option;
Grant all privileges on.To 'root' @ '118. 192.91.xxx' identified by 'mypassword' with grant option;

Query the user table again:

Then # mysql-u root-p xxxx, login successful!

Check the difference between mysql-h localhost and mysql-h 127.0.0.1.UNIX socketAnd connect to mysql through 127.0.0.1 is to useTCP/IP. Check the status:
Mysql-h localhost> status
Connection id: 639
Current database: mysql
Current user: root @ localhost
SSL: Not in use
Current pager: stdout
Using outfile :"
Using delimiter :;
Server version: 5.6.15-log Source distribution
Protocol version: 10
Connection: Localhost via UNIX socket

Mysql-h 127.0.0.1> status
Connection id: 640
Current database: mysql
Current user: root @ localhost
SSL: Not in use
Current pager: stdout
Using outfile :"
Using delimiter :;
Server version: 5.6.15-log Source distribution
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP