Neil Conway <neilc@samurai.com> writes:
> Well, I realize that stddev(DISTINCT x) != stddev(x) and that most
> people are going to be interested in stddev(x), but I don't think it's
> inconceivable for someone to be interested in stddev(DISTINCT x).
> Explicitly checking for and rejecting it doesn't serve any useful
> purpose that I can see, beyond compliance with the letter of the
> standard -- if the user asks for stddev(DISTINCT x), are we really
> providing useful behavior if we refuse to calculate it?
Agreed, refusing this is not something we should waste code on.
regards, tom lane