There is a stored procedure called GetClients that returns a list of all client records. GetClients is called by other applications in the organisation (cannot be changed). The report is to display data for either: All clients if the user does not select a client, or The selected client. I have created a dataset that calls the GetClients stored procedure. I have created a report parameter @Client whose Available Values are obtained from the dataset. But when I run the report, SSRS does not allow the @Client parameter to be not selected. It displays a message saying "Please enter a value for the parameter 'Client'" It does this even when I have Allow NULL values and/or Allow blank values. How can I resolve this?
It seems like you have a multi select parameter. In such case it cannot be null or blank. In this case you should add a special item for eg. All. Or do not use multi selection param if you do not need it.