Syntax:
SHOW GRANTS [FOR user]

This statement lists the GRANT statement or statements that must be
issued to duplicate the privileges that are granted to a MySQL user
account. The account is named using the same format as for the GRANT
statement; for example, 'jeffrey'@'localhost'. If you specify only the
user name part of the account name, a host name part of '%' is used.
For additional information about specifying account names, see [HELP
GRANT].

mysql> SHOW GRANTS FOR 'root'@'localhost';
+---------------------------------------------------------------------+
| Grants for root@localhost                                           |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
+---------------------------------------------------------------------+

To list the privileges granted to the account that you are using to
connect to the server, you can use any of the following statements:

SHOW GRANTS;
SHOW GRANTS FOR CURRENT_USER;
SHOW GRANTS FOR CURRENT_USER();

As of MySQL 5.1.12, if SHOW GRANTS FOR CURRENT_USER (or any of the
equivalent syntaxes) is used in DEFINER context, such as within a
stored procedure that is defined with SQL SECURITY DEFINER), the grants
displayed are those of the definer and not the invoker.

URL: http://dev.mysql.com/doc/refman/5.1/en/show-grants.html

