Hi,
In order to view the SQL code of the report, you must first get hold of the report definition file (XML). You can get this from your supplier or by going to the reports section in CRM and download the report from the actions menu. Once you get hold of this file, then you can open it in Visual Studio (if it has the Reporting installed as well). In Visual Studio you can get to the source of the code.
Ofcourse you can also open the XML file in notepad or your favorite xml viewer and look for the SQL code.
Good luck,
Ronald Lemmen