Re: [sqlite] windowing functions != recursive functions

2005-10-13 Thread pilot pirx
ventually migrated to the core if there is a sufficient interest. - Original Message - From: [EMAIL PROTECTED] To: sqlite-users@sqlite.org Subject: Re: [sqlite] windowing functions != recursive functions Date: Wed, 12 Oct 2005 22:48:35 -0400 > > "pilot pirx"

Re: [sqlite] windowing functions != recursive functions

2005-10-13 Thread Andrew Piskorski
On Wed, Oct 12, 2005 at 09:05:26PM -0500, pilot pirx wrote: > There is no problem in computing moving average > or cumulative sum etc > with the existing SQL (or dealing with time windows > in general) - it just the SQL gets nasty - examples Except that the SQL doesn't "just" get nasty, it can

Re: [sqlite] windowing functions != recursive functions

2005-10-13 Thread Andrew Piskorski
On Wed, Oct 12, 2005 at 09:05:26PM -0500, pilot pirx wrote: > The windowing functions described in the link > are different from recursive functions. Yes, I think you're right. Your EMA example bugged me, so I fooled with it, but I couldn't come up with any way to implement EMA using plain SQL,

Re: [sqlite] windowing functions != recursive functions

2005-10-12 Thread drh
"pilot pirx" <[EMAIL PROTECTED]> wrote: > Now, for the recursive function like exponential moving average > the defintion is that > > ema(i+1) = val(i) * coef + ema(i) * (1-coef). > > That is I have to know the previous value of both EMA _and_ VALUE > (while for moving avearage I need to kno

[sqlite] windowing functions != recursive functions

2005-10-12 Thread pilot pirx
I was unaware of the windowing functions discusssion. Having a look at the first link, it looks like we may be talking about two subtly different issues. The windowing functions described in the link are different from recursive functions. There is no problem in computing moving average or cumulat