NULL Value in Crystal Reports Parameter

[#1]

I have trouble getting a parameter work in Crystal Reports. I have defined a Parameter variable in the report. The parameter should restrict the data if a value is entered or it has to bring back all the data if the Value is NULL. In the SELECT EXPERT I have a condition that says IF ISNULL (Parameter_FIELD) then a Default Value.

When I run the report I get an error saying that the Parameter has NULL Value. Even If I default it with some Value the report is not working the way we want to. Is there a way I can do what I am trying to achieve. Please advice.

[Former Member]

Dear,

Use this formula

(not HasValue({?My Parameter}) OR {TABLE.FIELD} = {?My Parameter})