The Query returned no rows for the data set

If you are using RTC and previewing certain reports you probably will run into this error. “An error occurred during local report processing.” The Hidden expression for the textbox ‘……’ contains an error: The query returned no rows for the data set. The expression therefore evaluates to null.

I searched around and didn’t find any info on this and started researching with trial and error and found that it is simply not an error from NAV perspective. It simply means that there is not data to print. The way RTC reports work is that the reports are generated as XML files on service tier and sent to the client which uses it as a data source to render the RDL.
This simply means based service tier returned an empty xml file. So why would service tier return an empty xml file. After looking at different reports, I’ve concluded that if PrintOnlyIfDetail property on a data item is set, then Service tier removes parent records if there are no children.
I suggest telling your customers/ end users that there is no data based on filters. If they are not ok with it, then you have to dummy integer data item at the end of the report and set it to print one blank line if there are no Parents data item to print.