Adriano Fernandes added new Window functions from the SQL:2008 standard

From twitter

I remember when I added the LOWER function to Firebird. I needed to grep (for nod_upper) and change dozens of files…
Now to add even a window function (which the framework is prepared to) it takes just a few localized changes http://bit.ly/uAt3ZP…
Now adding LAST_VALUE and NTH_VALUE.

You can read more about the list of window functions that are already implemented or needs to be implemented on the tracker

A short description of what these functions do :

first_value(value any) return value evaluated at the row that is the first row of the window frame
last_value(value any) returns value evaluated at the row that is the last row of the window frame
nth_value(value any, nth integer) returns value evaluated at the row that is the nth row of the window frame (counting from 1); null if no such row
for ref : http://www.postgresql.org/docs/9.1/static/functions-window.html#FUNCTIONS-WINDOW-TABLE