Of course, avg() is already in the spec, so this isn't the 'perfect'
instance,
You can easily maintain an average as you see each row at the cost
of more divisions. (eg for the 9th item add one ninth of the difference
between the item and the running average to the average).
Calculating a media
-Original Message-
From: Roger Binns [mailto:[EMAIL PROTECTED]
Sent: Monday, December 06, 2004 7:26 PM
To: [EMAIL PROTECTED]
Subject: Re: [sqlite] Implementing aggregate user functions
> new API function. But I am loath to add new API functions without
> good reason and I do not c
new API function. But I am loath to add new API functions without
good reason and I do not consider performance optimization of an
exception condition a good reason. So you are going to have to
argue very hard to get such a thing implemented.
My motivation isn't based on performance, but on corre
Roger Binns wrote:
xFinal is always called.
That makes life easier. Is it possible to tell if xFinal wants
real results back versus there was an error earlier and I only
need to cleanup.
It is not possible at this time. xFinal called for cleanup
purposes only is an exception condition. One do
xFinal is always called.
That makes life easier. Is it possible to tell if xFinal wants
real results back versus there was an error earlier and I only
need to cleanup.
Roger
Roger Binns wrote:
It isn't 100% clear to me what the semantics are for implementing
aggregate user functions. The sqlite3_create_function call shows
that they are done via xStep and xFinal callbacks. I assume that
xStep is called for each relevant row. When is xFinal called?
If xFinal is always
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