I have faced suddenly the following issues with jasperstudio data set dialog:
First: After running the first query "select KN_Perzentile..." and clicking the refresh preview data the jasper shows that 2 fields are read (which should be one in fact), but the data will not shown at all!
Second: Running the second query "select top..." encounters an error, saying that the field KN_Perzentile is not found! This field is not asked in the second query at all!
both queries are tested against Database and correct. I did not have these issues till today