I'm sorry for being a SQL noob. Can you elaborate on what is wrong with this, and what would be the way to write it without causing the scale of problem described in the OP?
(user=671156 AND permission=16 AND org=101) OR 102
org IN (101, 102)It is often worth running a SELECT on the WHERE clause you are about to use for your UPDATE. That way you can make sure only a limited amount of data comes back before you launch something catastrophic.
It should be
UPDATE permissions SET allow = 1 WHERE user=671156 AND permission=16 AND org=101 OR org=102; (user=671156 AND permission=16 AND org=101) OR (org=102)