I am afraid there is currently no easy way of doing this. The default is that for a text parameter that is a string an empty string is forwarded as an empty string rather than NULL. While for other datatypes (e.g., Integers) an empty string is NULL. You could hack ReportServer here and, for example, adapt parameters on report execution, but there is no clean way of doing this. The best way would probably to have this configurable in the parameter settings.
About the Integer, I have been noticing that I cannot leave an empty value, if the text parameter is an integer data type.
As soon as I ve been trying to run the preview, reportserves shows up a red symbol, like a warning, because it wants a value.
Since we have reports with text parameter , as integer, but they can be empty before running. How can I workaround this?
Thanks again,
Cheers,
Alex
for completeness:
we added an option for text parameters: “return null on empty” (RS-1953). This will be available in reportserver 3.0.6, available by the end of the year.
For integers and other data types, we return null if they are left empty. Only if the “mandatory” option is set, the user gets an error if the parameter value is empty.