Alternate "Criteria" in a query

[pgscannell]

I have a query that is the backbone for a sub form. there are 2 required parameters and one optional one.

The required parameters are: Employee and Start date
So, in the query, under the Employee I have the code:
[Forms]![frm_new_CSTRACK]![cmbEMPLOYEE]
and under the Start_Date I have the code:
[Forms]![frm_new_CSTRACK]![datStartDate]

The optional parameter is Process Step. So I need the code that would provide a criteria if there was something in the field, or do nothing if it was blank. I tried this:
IIf ( [Forms]![frm_new_CSTRACK]![cmbPROC_STEP] is not null, [Forms]![frm_new_CSTRACK]![cmbPROC_STEP], Null )

but it didn't work. I got no data at all.

Anyone know how to do this?

Thanks in advance,
Paul

 

[pbaldy]

I often use this technique:

http://www.mvps.org/access/queries/qry0001.htm