Re: Calculating a moving average

Why not use a cursor?

P.S.

A moving average will look much better if you Hahn the tails.

To do a normal 7 point moving average, you take (x[i]+ x[i+1]+ x[i+2]+
x[i+3]+ x[i+4]+ x[i+5]+ x[i+6])/7 as point xprime[i] and (y[i]+ y[i+1]+
y[i+2]+ y[i+3]+ y[i+4]+ y[i+5]+ y[i+6])/7 as point yprime[i].

But when you start let x[0], y[0] be the first point, and then average
the next 2 for the second point... until you get to 7 and then do the
same thing in the other end. Otherwise, you get a very strange looking
curve.

IMO-YMMV

________________________________

From: pgsql-general-owner(at)postgresql(dot)org
[mailto:pgsql-general-owner(at)postgresql(dot)org] On Behalf Of Vanole, Mike
Sent: Wednesday, January 19, 2005 1:34 PM
To: pgsql-general(at)postgresql(dot)org
Subject: [GENERAL] Calculating a moving average

Hi,

I need to calculate a moving average and I would like to do it with SQL,
or a Pg function built for this purpose. I'm on Pg 7.4. Is this possible
in Pg without a bunch of self joins, or is there a funtion available?

Thanks,

Mike