MEDIAN in Oracle Discoverer

Does anyone know how to solve this problem: I need to make a Discoverer report containing the median age of people matching certain criteria, say I need the number of graduates graduated 1999, 2000 and 2001 as well as their median age, sorted by their majoring subject. I can easily enough write a normal SQL-query to find the middle element in a sorted list, but with Discoverer it isn't that easy, as the positioning of the axis elements, the conditions used etc all affect the set of data from which the median age is to be selected. I would like the solution to be easy on the end user, so the optimal solution would be to have a drag-and-droppable object defined on the EUL level, as opposed to having a report-specific calculated item defined on Discoverer User-level.

All my options, as I see it, are:

• a calculated item (how should I define the set of ages to pick the median from?) on Discoverer User level.
• a PL/SQL-function (what parameters should it have?), called from a calculated item in Discoverer User Edition or from a EUL level item defined in the Admin Edition
• a MEDIAN-Item in the same EUL-folder that contains the people's ages (although, as it is out of context, defining the median might not be that easy **)

None of these seem straightforward. I actually don't even know where to begin...

How are the other available statistical functions (AVG etc) implemented? Is there any reason why I couldn't implement median in a similar way?

Any help appreciated,

    Kim Johnsson

• an idea I had was to define the median age item in the EUL folder as the PL/SQL-selected median age divided by the actual item count. That way, all the individual items in the report would accumulate towards the final median value, i.e. (MEDIAN / count) * count = MEDIAN. Don't know how to do that, though, as it needs a context...