Re: wip: functions median and percentile

2010/8/19 David Fetter <david(at)fetter(dot)org>:
> On Thu, Aug 19, 2010 at 12:12:12PM -0500, Kevin Grittner wrote:
>> David Fetter <david(at)fetter(dot)org> wrote:
>>
>> > Median may be useful, but we pretty much can't just call it
>> > "median." Instead, we need to call it something like "left_median"
>> > or "arithmetic_median."
>>
>> I think it would be reasonable, and perhaps preferable, to use just
>> "median" for the semantics described in most dictionaries -- for
>> example, this:
>>
>> http://www.merriam-webster.com/dictionary/median
>>
>> If you do a google search for "median" and poke around, you'll find
>> many places where this is the only definition mentioned; the others
>> seem to be rather infrequently used.  Why not make the commone usage
>> convenient?
>
> The reason not to is the same reason that MEDIAN doesn't appear in the
> SQL standard, namely that what's common in one field is wrong in
> another.

I think some else. The reason can be more simple - implementation of
median is significantly harder then other aggregates.

I looked there and Oracle11g use "median" in common sense.

Regards

Pavel Stehule
>
> Cheers,
> David.
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