// Group by + Order by
public DataNode <string, Cell> Groupby(IEnumerable <string> indexColumns, string leafColumn)
{
if (_grouper == null)
{
_grouper = new TableGrouper(_dataTbl);
}
return(_grouper.GroupBy(indexColumns, leafColumn));
}
private void FetchTable()
{
_dataTbl = _dataProvider.Fetch();
_grouper = new TableGrouper(_dataTbl);
}
