title: hibernate criteria group Query is wrong
body: <p>I am trying to generate the following query using Criteria:</p>
  
  <pre><code>select order_number, order_date, sum(order_amount)
  from st_pur_orders
  group by ORDER_NUMBER,ORDER_DATE;
  </code></pre>
  
  <p>Here is my Criteria:</p>
  
  <pre><code>  Criteria cr = session.createCriteria(StPurOrders.class);
              cr.setProjection(Projections.projectionList()
                      .add(Projections.property("orderNumber"), "orderDate")
                      .add(Projections.sum("orderAmount"))
                      .add(Projections.groupProperty("orderNumber"))
                      .add(Projections.groupProperty("orderDate")));
              cr.setResultTransformer(Transformers.aliasToBean(PurOrderColl.class));
              list = cr.list();
  </code></pre>
  
  <p>But the query getting generate in the background is this:</p>
  
  <pre><code>select this_.ORDER_NUMBER as y0_, sum(this_.ORDER_AMOUNT) as y1_,
      this_.ORDER_NUMBER as y2_, this_.ORDER_DATE as y3_
  from STOCK.ST_PUR_ORDERS this_
  group by this_.ORDER_NUMBER, this_.ORDER_DATE;
  </code></pre>
  
  <p>My Question is why is the <code>ORDER_NUMBER</code> field being listed twice?</p>