jsp distinct

[briglia23]

hi. i have this method:

public Set listTaglie() throws Exception {
		try {
			Set<Scheda> ret = new HashSet<Scheda>();
			ret.addAll(manager.createQuery("from Scheda").getResultList());
			return ret;
		} catch (Exception e) {
			log.error("listTaglie() - Failed to list Taglie: "+e);
			throw e;
		}
	}

I want a query like this:
select distinct taglia_scheda from scheda;
How can i make it?
Thank you