Taking a look at account permissions

MySQL uses account permissions to specify who can do what. Anyone using a valid account can connect to the MySQL server, but he or she can only do those things that are allowed by the permissions for the account. For example, an account might be set up so that users can select data but cannot insert or update data.
Permissions can be granted for particular databases, tables, or columns. For instance, an account can be set up that allows the user to select data from all the tables in the database but insert data into only one table and update only a single column in a specific table.
Permissions are added by using the GRANT query and removed by using the REVOKE query. The GRANT or REVOKE query must be sent using an account that has permission to execute GRANT or REVOKE statements in the database. If you attempt to send a GRANT query or a REVOKE query using an account without grant permission, you get an error message. For instance, if you try to grant permission to use a select query, and you send the query using an account that does not have permission to grant permissions, you might see the following error message: grant command denied Permissions can be granted or removed individually or all at once.
Permission &Description
ALL All permissions
ALTER Can alter the structure of tables
CREATE Can create new databases or tables
DELETE Can delete rows in tables
DROP Can drop databases or tables
FILE Can read and write files on the server
GRANT Can change the permissions on a MySQL account
INSERT Can insert new rows into tables
SELECT Can read data from tables
SHUTDOWN Can shut down the MySQL server
UPDATE Can change data in a table
USAGE No permissions
Granting ALL is not a good idea because it includes permissions for administrative operations, such as shutting down the MySQL server. You are unlikely to want anyone other than yourself to have such sweeping privileges.