Re: Idempotence and "Replication Insensitivity" are equivalent ?

<pamelafluente_at_libero.it> wrote:
> this is an exaggeration. Everyone knows that the variance is simply
> the difference between the second moment and the square of the
> first moment. So you just need to accumulate values and their squares.

Ah. In that case, variance (and standard deviation) are efficient aggregate functions.

-- 
Chris Smith