Get the middle part of a result set

Hi,

I have to following problem:

I get X rows from a statement, these are sorted by a certain column, let's say an numerical value.
Now I want to calculate the average of this numerical value, but the 10% with the lowest and the 10% with the highest value shall not be included in this calculation.
So for example, if I get 20 rows, I need the average of the value in rows 3 to 18.

Currently I solved this with a very complicated statement, but I don't know the built-in Oracle mathematical functions so I hope that there could be a way to do this with a better performance.

Thanks for any hints,

Jens Received on Tue Dec 18 2007 - 02:17:49 CST