CAML and GroupBy

Hi All,

please help how to use GroupBy on sharepoint, SelectCommand of SPDataSource:

<View><Query><GroupBy  Collapse="TRUE"><FieldRef Name="Date"/></GroupBy><OrderBy><FieldRef Name="Date" Ascending="FALSE"/></OrderBy></Query><ViewFields><FieldRef Name="Date"/></ViewFields></View>

Result does not groups the dates as expected.