Обсуждение: Fwd: [SQL] aggregate function stddev

Folks,

Sending this remark to the list so that I/we don't forget to patch it .....

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Just noticed that the postgres stddev is the stddev_sample formula.
There are two different ways to calculate this value.
Their difference is very small with large samle size.  It would be nice
to distinguish the two different versions.
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--
Josh Berkus
Aglio Database Solutions
San Francisco

Josh Berkus <josh@agliodbs.com> writes:
> Sending this remark to the list so that I/we don't forget to patch it .....

> ========================================
> Just noticed that the postgres stddev is the stddev_sample formula.

The documentation already points out that stddev is the sample standard
deviation.

            regards, tom lane