Handling of null values when filtering with Top N

dsualeh

Hi ,

I using an xml data set to render a table to display a person's academic history.

The columns in this table are Degree , Year , School and Major.

I have set up a sort criteria on Year in descending order (integer column).

And a filter criteria of Top 3 on Year column.

The year column may have null values for some records in the data set

Suppose if there are only 3 records in the data set for academic history of which only 2 records have a value for Year.

I was expecting the filter criteria to give the 3 records in sorted order.

Obviously the third record would be having a null value for the Year column.

But I get only 2 records ?

Is this because sorting and filtering are done independently in BIRT ?

Is there a work around ? Does Top N ignore null values in the data set ?