You can run Sql Profiler against your database server to see the exact Sql that Crystal Reports is running to generate the report.
Sql Profiler is a tool that comes with Sql Server (under Performance Tools in your Sql Server programs) that shows every Sql statement hitting the database. Run a trace on your Sql Server through Sql Profiler then run your report and Sql Profiler will show you the exact Sql statements that your Crystal report is running against the database.