Average - Pg 9.2

[Patrick B <patrickbakerbr@xxxxxxxxx>]

Hi guys,

I've got a table which has id and created date columns.

I want to get the average of inserted rows monthly.

How can I get this data?

This query is not working as it is showing me same data in both columns.

select created_date,

AVG(id) 

OVER(ORDER BY created_date) AS avr from test

http://sqlfiddle.com/#!15/3289b/1

Thanks!
Patrick