MySQL account problem

Including the old client landing Mysql5.0 problem
Because the new version of Mysql5.0 used only MD5 encryption, so if the client is 3.5 version of the words to use the following statement to change the encrypted password
mysql> SET PASSWORD for ' some_user ' @ ' some_host ' = Old_password (' Mypass ');
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You can add a new user by issuing a GRANT statement:

shell> MySQL--user=root MySQL
Mysql> GRANT all privileges in *.* to Monty@localhost
Identified by ' something ' with GRANT OPTION;
Mysql> GRANT all privileges in *.* to monty@ "%"
Identified by ' something ' with GRANT OPTION;
Mysql> GRANT reload,process on *.* to Admin@localhost;
Mysql> GRANT USAGE on *.* to Dummy@localhost;

These grant statements install 3 new users:

Monty
You can connect to a full superuser from anywhere, but you must use a password (' Something ' to do this.) Note that we must issue a grant statement to Monty@localhost and monty@ "%". If we add a localhost entry, an entry created by mysql_install_db for the localhost anonymous user entry when we connect from the local host is preferred, because it has a more specific host field value, so it's an earlier arrival in the user table order.
Admin
Users who can connect from localhost without a password and are granted reload and process management privileges. This allows the user to perform mysqladmin reload, mysqladmin refresh and mysqladmin flush-* commands, as well as Mysqladmin processlist. No permissions are granted to the database. They can authorize it later by issuing another grant statement.
Dummy
A user can connect without a password, but only from the local host. Global permissions are set to ' N '--usage permission type allows you to set a user without permission. It assumes that you will grant database-related permissions at a later time.