Are you trying to use the SQL Command feature in Crystal? Yes, you can use a Crystal parameter with SQL.
1) go to your Database Expert, ODBC connection
2) click on Add Command, a new screen "Add Command to Report" will pop up
3) type in your select statement (query)
4) on the right side of the pop up screen, you will see a small window called "Parameter List"
5) Create your parameter there and select it in your query
You are done!