title: NHibernate QueryOver group by without selecting the grouped by column
body: <p>Having a query like the following:</p>
  
  <pre><code>var subquery = SessionFactory.GetCurrentSession()
      .QueryOver&lt;SomeEntity&gt;()
      .Where(_ =&gt; _.SomeOtherEntity.Id == someId)
      .SelectList(list =&gt; list
          .SelectGroup(x =&gt; x.SomeGroupByProperty)
          .SelectMax(x =&gt; x.MaxPerGroupProperty))
      .List&lt;dynamic&gt;();
  </code></pre>
  
  <p>The generated sql is selecting both <code>SomeGroupByProperty</code> and maximum of <code>MaxPerGroupProperty</code>. Is it possible to get it to group on <code>SomeGroupByProperty</code> but only select maximum of <code>MaxPerGroupProperty</code>? This is for using the subquery result with a contains in parent query.</p>