Syntax:
REVOKE priv_type [(column_list)] [, priv_type [(column_list)]] ...
    ON [object_type] {tbl_name | * | *.* | db_name.*}
    FROM user [, user] ...

REVOKE ALL PRIVILEGES, GRANT OPTION FROM user [, user] ...

The REVOKE statement enables system administrators to revoke privileges
from MySQL accounts. To use REVOKE, you must have the GRANT OPTION
privilege, and you must have the privileges that you are revoking.

Each account is named using the same format as for the GRANT statement;
for example, 'jeffrey'@'localhost'. If you specify only the username
part of the account name, a hostname part of '%' is used. For
additional information about specifying account names, see [HELP
GRANT].

For details on the levels at which privileges exist, the allowable
priv_type values, and the syntax for specifying users and passwords,
see [HELP GRANT]

URL: http://dev.mysql.com/doc/refman/5.0/en/revoke.html

