If you can’t get away from your databases, you can at least talk to them from your iPhone using the iPhone version of jHeidi (presumably not using Java on the iPhone…). Supports Oracle and MySQL, only $3.99.
So if your MySQL query is mysteriously giving you an error about an ‘unknown column’ in the ‘on clause’, it’s possibly because in MySQL 5.0.12 the handling of the left join was changed to conform to the SQL standard. Basically it means that because of changes to precedence you’ll probably have to re-order your list of tables in the from statement. Documentation here. Discussion of the problem here.