title: OData v4.0 aggregate queries (aggregate query syntax)
body: <p>For example,
  I have an object model:</p>
  
  <pre><code>Product
  { 
    int ProductId,
    string Name,
    List&lt;Sale&gt; Sales
  }
  </code></pre>
  
  <ul>
  <li>I want to use the aggregate queries to get total Amount of Sales:</li>
  </ul>
  
  <p><strong>GET: Product?$apply=groupby(Name, aggregate(Sales(Amount with sum as Total)))</strong> <em>(follow as oasis-open standard)</em></p>
  
  <p>--> Got error: <em>UriQueryExpressionParser_CloseParenOrCommaExpected=" ')' or ',' expected at position {0} in '{1}'.</em> ". position at Amount.</p>
  
  <ul>
  <li>I change the query to: </li>
  </ul>
  
  <p><strong>GET: Product?$apply=groupby(Name, aggregate(Sales/Amount with sum as Total))</strong></p>
  
  <p>--> Work successfully!.</p>
  
  <p><strong>My question</strong>:</p>
  
  <p>--> Had current version OData Core supported the aggregate query syntax as my example "<strong>aggregate(Sales(Amount with sum as Total))</strong>" or NOT?</p>
  
  <p>Please give me your advice.</p>
  
  <p>Thank you very much</p>