title: SQL error on UPDATE view with GROUP BY
body: <p>This is the view</p>
  
  <pre><code>SELECT src.OfferAngebotsnummer AS OAngNr1, 
         SUM(src.Summe2) AS Summe,  
         CSDokument_1.OfferAngebotsnummer AS OAngNr2,  
         CSDokument_1.Auftragsvolumen
  FROM (
       SELECT OfferAngebotsnummer, 
              ROUND(Angebotssumme, 2) AS Summe2
       FROM dbo.CSDokument
       WHERE (MANeu = 'AS400') AND 
             (Art = '3') AND 
             (DokumentTyp = '3')) AS src 
       INNER JOIN
             dbo.CSDokument AS CSDokument_1 ON 
             src.OfferAngebotsnummer = CSDokument_1.OfferAngebotsnummer
       GROUP BY src.OfferAngebotsnummer,
                      CSDokument_1.OfferAngebotsnummer, 
                      CSDokument_1.Auftragsvolumen
  </code></pre>
  
  <p>And this is the <code>UPDATE</code> statement</p>
  
  <pre><code>update UpdateAuftragsvolumenAngebot
  set Auftragsvolumen = Summe
  where Auftragsvolumen &lt;&gt; Summe
  </code></pre>
  
  <p>But I get an error that it's not allowed to use <code>UPDATE</code> on view with <code>group by</code> clause. </p>
  
  <pre><code>Cannot update the view or function 'UpdateAuftragsvolumenAngebot' 
  because it contains aggregates, or a DISTINCT or GROUP BY clause, 
  or PIVOT or UNPIVOT operator.
  </code></pre>
  
  <p>How can I accomplish the <code>UPDATE</code>?</p>