使用JPA的createNativeQuery执行复杂sql

	public List queryLatestPerfDailyViewIdAndDate() {
		List<CalcPerfDailyViewEntity> result = new ArrayList<CalcPerfDailyViewEntity>();
		String sql ="select  ID, max(TradeDate) as TradeDate from calc_perf_daily_view group by ID";
		Query query = em.createNativeQuery(sql);
		List<Object[]> vlist = query.getResultList();
		for(Object[] v : vlist){
			CalcPerfDailyViewEntity entity = new CalcPerfDailyViewEntity();
			entity.setId(v[0].toString());
			DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
			try {
				entity.setTradedate(df.parse(v[1].toString()));
			} catch (ParseException e) {
				e.printStackTrace();
			}
			result.add(entity);
		}
		return result;
	}