Depending on how you're using the SQL Expression, you may not be able to use a subreport. In that case, you could write a Command to provide the data for your report. A Command is a SQL Select statement using the syntax of the database you're connected to. If you've created parameters in your main report to filter the data, you'll need to delete those parameters and re-create them in the Command Editor in order to filter the data there. A couple of best practices for using commands:
1. Do not link a command to any tables or other commands. Instead use a single query to return all of the data that's required in the report.
2. Do not filter the report data in the Select Expert. Instead, do the filtering in a Where clause in the Command.
Not following these rules will cause reports to be slow because Crystal will not be able to push the processing down to the server. Instead, it will pull all of the data into memory and link or filter the data there which can be very inefficient.
-Dell