Block user access to certain tables

DBMS allows the admin to grant table access to a user using something like: GRANT ALL ON mydb.mytbl1, mydb.mytbl2 TO 'someuser'@'somehost'; However, is it possible to grant all tables to a user and explicitly block access to some of them? For example (The BLOCK key word is a fake one and is only used for illustration.): GRANT ALL ON mydb.* TO 'someuser'@'somehost'; BLOCK ALL ON mydb.mytbl3 TO 'someuser'@'somehost'; Another idea is to add a where clause to the GRANT statement. However, it seems that the GRANT statement syntax does not allow that (http://dev.mysql.com/doc/refman/5.1/en/grant.html) . This kind of access control might be convenient if the admin trust the user in most cases (e.g. 1000 tables) and only want to block access to a small number of top sensitive tables. Could you please tell me whether such kind of mechanism exists?