Strange behavior of a calculated field in an MS Access query

Question

This question is curious for me.

I've created the following function in VBA

Public Function ContajeDeMaterialAUnaFecha(DFechaDeContaje As String, _
                                            StrDescMatProveedor As String) As Single
Dim rst As DAO.Recordset
Dim rstResultado As DAO.Recordset
Dim strSQL As String
Dim sngUnidadesContadas As Single
Dim intCuentas As Integer
    strSQL = "SELECT materialproalbsub.nalbpro, materialproveedor.DESC_MAT_PROVEEDOR, " & _
                "materialproalbsub.TOTALCANTIDAD, materialproalbsub.precioud, materialproalbsub.falbaran " & _
                "FROM materialproveedor INNER JOIN materialproalbsub ON materialproveedor.idmaterialemp = " & _
                "materialproalbsub.idmaterialemp " & _
                "ORDER BY materialproalbsub.falbaran;"

    Set rst = CurrentDb.OpenRecordset(strSQL, dbOpenSnapshot, dbSeeChanges)

    rst.Filter = "materialproalbsub.falbaran<=#" & DFechaDeContaje & "# " & _
            "AND materialproveedor.DESC_MAT_PROVEEDOR='" & StrDescMatProveedor & "'"

    Set rstResultado = rst.OpenRecordset

    If rstResultado.RecordCount > 0 Then

        intCuentas = 0
        sngUnidadesContadas = 0

        rstResultado.MoveLast
        rstResultado.MoveFirst

            Debug.Print rstResultado.RecordCount, StrDescMatProveedor

            Do Until rstResultado.EOF

                sngUnidadesContadas = sngUnidadesContadas + rstResultado.Fields("TOTALCANTIDAD")

                rstResultado.MoveNext

                intCuentas = intCuentas + 1

            Loop

        Debug.Print DFechaDeContaje, sngUnidadesContadas

        ContajeDeMaterialAUnaFecha = sngUnidadesContadas

    End If

    rst.Close
    Set rst = Nothing

    rstResultado.Close
    Set rstResultado = Nothing

End Function

That function is called in a Query from Access, as that (in SQL mode):

SELECT materialproalbsub.nalbpro, materialproveedor.DESC_MAT_PROVEEDOR, materialproalbsub.TOTALCANTIDAD, materialproalbsub.precioud, materialproalbsub.falbaran, ContajeDeMaterialAUnaFecha([falbaran],[materialproveedor]![DESC_MAT_PROVEEDOR]) AS TotalesAFecha
FROM materialproveedor INNER JOIN materialproalbsub ON materialproveedor.idmaterialemp = materialproalbsub.idmaterialemp
WHERE (((materialproveedor.DESC_MAT_PROVEEDOR)<>"- Seleccione uno de la lista -"))
ORDER BY materialproalbsub.falbaran;

Function works fine, and also the Query from MS Access, but there is a serious problem: the query is constantly recalculated once executed (any cell selection in the result, any scroll).

Is it possible to execute it only once?

Thanks in advance

Answer 1

The reason seems to be from your where clause

WHERE (((materialproveedor.DESC_MAT_PROVEEDOR)<>"- Seleccione uno de la lista -"))