Non-Access or -base QBE tool?

I'm currently looking for a QBE tool that can execute queries on PostgreSQL or MySQL.

OS doesn't really matter.

Reason is that we've got to do QBE at school but I don't want to use neither Microsoft Access nor OpenOffice.org Base (lack of features).

Any help would be appreciated.

I find the MS Access works quite well as a front-end for MySQL when a 'quick' front-end is needed. For something more robust I would recommend HeidiSQL.