It's not hard to get around this limitation if you have fairly good SQL skills.  I would do the following:

 

1.  Create a new report (this is MUCH easier than editing an existing rpt!)

2.  Outside of Crystal, create a query that will return ALL of the data for your report, including the expression where you want to use the parameter.

3.  In your report, instead of selecting tables, create a Command.

4.  Add the SQL created in step 2 to the command.

5.  For each parameter in the query, create a parameter in the Command Editor.  NOTE:  Commands will NOT work with params that are created in the report itself!

6.  For each parameter you want to use in the query, place your cursor where you want the param, then double-click on the parameter.  NOTE:  if any of your commands are strings, you will have to put quotes around the parameter in the query.  For example: '{?MyStringParam}'

7.  Save the command.

8.  Design your report.

 

-Dell