Restricted query

Hello list,

This is an inventory system where some users are restricted to view only
certain suppliers, those restrictions are in a table called pedusers
(username,supplierallowed), there are other kind of "superuser" who are
not restricted, actually I created another table for them (userexcept).
To select restricted rows I use this code:

select * from prvdor
where prvtiprov = 2 and
prvpk in
(select usr_prvdor from peduser where
usr_login = 'default')

I think I would write this in a return set function instead but I would
like to know others ways to write a SQL sentence to return the rows
according users permission/restrictions.

Thanks in advance for your comments

--
Sinceramente,
Josué Maldonado.

"Vivir sin filosofar es, propiamente, tener los ojos cerrados, sin
tratar de abrirlos jamás." -- Descartes