Crystal Reports Parameter with Like, Specific and ALL Clause Issue

Message

   My dataset has a field that shows City, State ZIP and sometimes country code as well. I need my parameter to gather sales info from the dataset, currently my parameter has the specific dataset listed as a drop down, but I also made it editable. I want the end user to be able to pick a specific City, State ZIP from the drop down or manually type in part of whats in the field, such as for Fresno, CA which may have multiple entries with different ZIP's if the user manually types in Fres I want the result to be every record that has Fres in it. 

So the formula I am trying to make thus far is as follows...
if {?CityStateZipParameter} = "ALL" then {CityStateZipDataset} = "*" else
{CityStateZipDataset} like {?CityStateZipParameter}

Not sure what I'm missing here. 

Any help would be greatly appreciated.