The difference between mysql-h localhost and mysql-h 127.0.0.1

My colleague said this morning that the MySQL root account was not logged in. I tried.
#mysql-U root-p
Tip "Access denied for user ' root ' @ ' localhost ' (using Password:yes)"

I was the first person who changed the root password because of the resignation of a colleague after years. Follow the forgot root password to reset your password:
#/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

With a new password or unable to log in, the prompt is the same as above. For a non-root account login, 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, sure enough to log in.
Prior to configuring the database The classmate did not give the ' root ' @ ' localhost ' and ' root ' @ ' IP ' authorization.
Grant all privileges the ' root ' @ ' localhost ' identified by ' mypassword ' with GRANT option;
Grant all privileges the ' root ' @ ' 118.192.91.xxx ' identified by ' mypassword ' with GRANT option;

Check the user table again:

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

Check the difference between mysql-h localhost and mysql-h 127.0.0.1, connect to MySQL via localhost using UNIX socket , Connecting to MySQL via 127.0.0.1 is using TCP/IP . Look at the status:  
mysql-h localhost > Status  
Connection ID:     639 
Current DATABASE:MYSQL&NBSP,
Current User:   [email protected] 
SSL:         & nbsp 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: [email protected]
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

Workaround
Added in My.cnf's [MySQL] section

Protocol=tcp

Save restart MySQL, problem solution
Summary

[Email protected]% means all access can be

[Email protected] indicates that localhost can access

The difference between mysql-h localhost and mysql-h 127.0.0.1