options of what is displayed when no data is selected

In sql server report 2005 (SSRS 2005), I will be generating some reports that may not have any data selected at times. This can you can tell me how can you display a message like 'The report is not generated since no records' were selected for this report. Can you tell me how to solve this problem either with sql and/or a sql server report 2005? If not no is selected, what will sql server report display? Would it display anything at all!

Thanks!