How do I retrieve my MySQL username and password?

I lost my MySQL username and password. How do I retrieve it?

Stop the MySQL process.

Start the MySQL process with the --skip-grant-tables option.

Start the MySQL console client with the -u root option.

List all the users;

SELECT * FROM mysql.user;

Reset password;

UPDATE mysql.user SET Password=PASSWORD('[password]') WHERE User='[username]';

But DO NOT FORGET to

Stop the MySQL process

Start the MySQL Process normally (i.e. without the --skip-grant-tables option)

when you are finished. Otherwise, your database's security could be compromised.

Unfortunately your user password is irretrievable. It has been hashed with a one way hash which if you don't know is irreversible. I recommend go with Xenph Yan above and just create an new one.

You can also use the following procedure from the manual for resetting the password for any MySQL root accounts on Windows:

1. Log on to your system as Administrator.
2. Stop the MySQL server if it is running. For a server that is running as a Windows service, go to the Services manager:

Start Menu -> Control Panel -> Administrative Tools -> Services

Then find the MySQL service in the list, and stop it. If your server is not running as a service, you may need to use the Task Manager to force it to stop.

3. Create a text file and place the following statements in it. Replace the password with the password that you want to use.

   UPDATE mysql.user SET Password=PASSWORD('MyNewPass') WHERE User='root';
   FLUSH PRIVILEGES;
   

   The UPDATE and FLUSH statements each must be written on a single line. The UPDATE statement resets the password for all existing root accounts, and the FLUSH statement tells the server to reload the grant tables into memory.

4. Save the file. For this example, the file will be named C:\mysql-init.txt.

5. Open a console window to get to the command prompt:

   Start Menu -> Run -> cmd

6. Start the MySQL server with the special --init-file option:

   C:\> C:\mysql\bin\mysqld-nt --init-file = C:\mysql-init.txt
   

   If you installed MySQL to a location other than C:\mysql, adjust the command accordingly.

   The server executes the contents of the file named by the --init-file option at startup, changing each root account password.

   You can also add the --console option to the command if you want server output to appear in the console window rather than in a log file.

   If you installed MySQL using the MySQL Installation Wizard, you may need to specify a --defaults-file option:

   C:\> "C:\Program Files\MySQL\MySQL Server 5.0\bin\mysqld-nt.exe" --defaults-file="C:\Program Files\MySQL\MySQL Server 5.0\my.ini" --init-file=C:\mysql-init.txt
   

   The appropriate --defaults-file setting can be found using the Services Manager:

   Start Menu -> Control Panel -> Administrative Tools -> Services

   Find the MySQL service in the list, right-click on it, and choose the Properties option. The Path to executable field contains the --defaults-file setting.

7. After the server has started successfully, delete C:\mysql-init.txt.
8. Stop the MySQL server, then restart it in normal mode again. If you run the server as a service, start it from the Windows Services window. If you start the server manually, use whatever command you normally use.

You should now be able to connect to MySQL as root using the new password.

An improvement to the most useful answer here:

1] No need to restart the mysql server
2] Security concern for a MySQL server connected to a network

There is no need to restart the MySQL server.

use FLUSH PRIVILEGES; after the update mysql.user statement for password change.

The FLUSH statement tells the server to reload the grant tables into memory so that it notices the password change.

The --skip-grant-options enables anyone to connect without a password and with all privileges. Because this is insecure, you might want to

use --skip-grant-tables in conjunction with --skip-networking to prevent remote clients from connecting.

from: reference: resetting-permissions-generic

Do it without down time

Run following command in the Terminal to connect to the DBMS (you need root access):

sudo mysql -u root -p;

run update password of the target user (for my example username is mousavi and it's password must be 123456):

UPDATE mysql.user SET authentication_string=PASSWORD('123456') WHERE user='mousavi';  

at this point you need to do a flush to apply changes:

FLUSH PRIVILEGES;

Done! You did it without any stop or restart mysql service.