Group by field UserMulti in view (Request CAML)

Question

I have a view where I have to do a group by a field UserMulti , I did the following:

 <Query>
      <GroupBy Collapse="TRUE" GroupLimit="30">
        <FieldRef Name="Utilisateur_Auteur" />
      </GroupBy>
      <OrderBy>
        <FieldRef Name="DtCreation"></FieldRef>
        <FieldRef Name="NDossier"></FieldRef>
        <FieldRef Name="Title"></FieldRef>
        <FieldRef Name="DCDecision"></FieldRef>
      </OrderBy>
    </Query>

But it does not work, it always displays all the Elements, the field Utilisateur_Auteur is an UserMulti.

You have solution ?

Answer 1

It seems GroupBy can not be applied on People or Group Fields which allows multiple entry. I have tried this CAML builder but no hope. Then I have tried to create a view and I did not find my field there. My filed name is Utilisateur_Auteur. It is missing when I select Group By dropdown.