However, unless tables included in your report are small, you really don't want to do this! When you join anything to a command, Crystal cannot push the join to the database. Instead, it will pull ALL of the data into memory and do the joins there.
Best practice with Commands is to include ALL of the data required for the report in a single command. Other Command best practices:
1. DO NOT use the Select Expert. This will also pull the data into memory and filter it there. Instead, put all of your filters in the Where clause.
2. If you're using parameters in the filter conditions, you MUST create the parameters in the Command Editor. Once you've created and used them there, you can edit them in the Field Explorer, but the Command Editor cannot see parameters that have been created in the Field Explorer.
3. You cannot use SQL Expressions with a command. Instead, include the code for the equivalent of the SQL Expression in the command.
-Dell