MySQL general SET-UP - mysql

Question

I am new to MySQL, and I got some general problems and thanks for any help:
My OS is MAC SnowLeopard, and when I type 'mysql' in terminal, I could successfully go into the mysql system, but, I have no rights to create databases:
mysql> create database A;
ERROR 1044 (42000): Access denied for user ''#'localhost' to database 'a'
I tried command line 'mysql -u root', I got the following:
ERROR 1045 (28000): Access denied for user 'root'#'localhost' (using password: NO)
I was thinking that I may set up the username for the database, which made me not possible enter mysql using root as username?
Then I tried 'localhost' as username, which I guess or remember I set it or not, using the command 'mysql -u localhost', I could successfully logged in to mysql, but STILL, cannot create database,
mysql> create database a;
ERROR 1044 (42000): Access denied for user ''#'localhost' to database 'a'
I am not sure:
why root not working;
weather I set up the username and password myself before...sorry...really have no memory now.
If I have set up the username as 'localhost' before, I cannot remember the password, therefore I have no rights to create database?
What should I do to recover the password, in the case of no root access?
If not possible, how to uninstall it? The PATH in .bash_profile for mysql is /usr/local/mysql/bin
I got a check: sudo port list installed | grep mysql
mysql5 #5.1.65 databases/mysql5
mysql5 #5.1.65 databases/mysql5
py26-mysql #1.2.3 python/py-mysql
does the mysql in /usr/local/mysql/bin refer to this one listed here?
Edit
The result of running ps -ef | grep mysql:
0 107 1 0 0:00.01 ?? 0:00.02 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/usr/local/mysql/data --pid-file=/usr/local/mysql/data/XXX-MacBook-Pro.local.pid
74 245 107 0 0:03.51 ?? 0:18.35 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --plugin-dir=/usr/local/mysql/lib/mysql/plugin --user=mysql --log-error=/usr/local/mysql/data/XXX-MacBook-Pro.local.err --pid-file=/usr/local/mysql/data/XXX-MacBook-Pro.local.pid
501 3790 417 0 0:00.00 ttys000 0:00.00 grep mysql
501 3337 1271 0 0:00.00 ttys001 0:00.01 mysql -u localhost

Answer 1

You'll need to reset your root password. To do this, follow those simple steps:
Stop MySQL: sudo port unload mysql5-server
Start MySQL using /opt/local/lib/mysql5/bin/mysqld_safe --skip-grant-tables &
Connect to MySQL: mysql -uroot
Reset your MySQL password:
mysql> use mysql;
mysql> update user set password=PASSWORD("NEW-ROOT-PASSWORD") where User='root';
mysql> flush privileges;
mysql> quit
Stop MySQL again sudo killall -9 mysqld_safe
Restart MySQL normally sudo port load mysql5-server
Connect to MySQL: mysql -uroot -p
EDIT
Added commands to stop/start MySQL.