I'm trying to build an expression for the criteria of a field in my query.
The criteria is If the value of a combobox on a form is not equal to "Show All" then to use the value of the combobox, otherwise allow all records (ie no criteria constraint).
I understand the syntax for the If statement and how to reference the form. The problem is that when the value of the box IS "Show All" i do not know how to allow all records to be returned.
I have tried a wildcard as below in the falsepart of the IIF statement, but I know this wont work because it's trying to match the literal string.
IIf([Forms]![myTestForm]![comboBox1]<>"Show All",[Forms]![myTestForm]![comboBox1],"*")
How do I have to structure the falsepart of the IIf statement to allow all values?