Error logging in My SQL

The % used when granting permissions represents a wildcard in MySQL, so the -h optional argument must be a separate hostname or IP address instead of % when connecting.

>mysql-h localhost-u root-p

Note that the -h option is optional if the MySQL server you are connecting to is running on the (localhost) machine where you want to run the command.

>mysql-u root-p

reference:
Connecting to MySQL Server|MySQL 5.6 Reference Manual