hide/unhide columns in an unbound subform in datasheet view

[pebbles_bam]

hello,
please please- i am a beginner and not very familiar with VBA
formname= frm_ETC
subformname=frm_sub
subform source : variable query, always named qry_ETC
this query can have a group by on 4 or 6 or 8 fields
depending on the groupby i only want to see the fields in de query
build by sql
i founded some code, used it as below, but it does not work:

Dim qdf As DAO.QueryDef
Set qdf = CurrentDb.QueryDefs("qry_ETC_High")


--selection in listbox
If list = "Highest Level" Then
qdf.SQL = " SELECT tbl_ETC_Plus.[Primary_role], tbl_ETC_Plus.[Investment_role], tbl_ETC_Plus.[Assignment_Role], tbl_ETC_Plus.[ETC_M],Sum(tbl_ETC_Plus.ETC) AS SumOfETC"
qdf.SQL = qdf.SQL & " FROM tbl_ETC_Plus"
qdf.SQL = qdf.SQL & " GROUP BY tbl_ETC_Plus.[Primary_role], tbl_ETC_Plus.[Investment_role], tbl_ETC_Plus.[Assignment_Role] , tbl_ETC_Plus.[ETC_M] "
Set qdf = Nothing
Me.frm_Sub.Form.Requery
Set qdf = CurrentDb.QueryDefs("qry_ETC_High")
Forms!frm_etc.frm_Sub.Form.RecordSource = "qry_ETC_High"
Me.frm_Sub.Form.Requery

with another selection in the listbox, more variale are in the groupby

subforms always shows all fields- but some then with value=#name

how to resolve this
many thanks for your attention