Using an iif

[Mark]

Hello All,

I have 2 combo box on a form. In a Subform I would like it to use the
selection in 1, or both comboBox, so I using a iif in the expresion.
However, I'm not getting all records with the iif I'm using now. I'm wanting
if cb is Null to get all records, but apparently a " " doesn't do it. What
does? Thanks

=IIf(IsNull([forms]![frmain]![cbpatientdetail]),"
",[forms]![frmain]![cbreferraldetail])

 

[Mark]

Sorry, I didn't do a search first or I would have had my answer.
For others here is the answer.

[cbreferraldetail] or [cbreferraldetail] is null

I have never really used the or before. Wow, powerful. I'm such a newbie.