Re: ANY_VALUE aggregate

On 12/5/22 18:56, David G. Johnston wrote:
> Also, maybe we should have any_value do something like compute a 50/50
> chance that any new value seen replaces the existing chosen value, instead
> of simply returning the first value all the time. Maybe even prohibit the
> first value from being chosen so long as a second value appears.

The spec says the result is implementation-dependent meaning we don't
even need to document how it is obtained, but surely behavior like this
would preclude future optimizations like the ones I mentioned?

I once wrote a random_agg() for a training course that used reservoir
sampling to get an evenly distributed value from the inputs. Something
like that seems to be what you are looking for here. I don't see the
use case for adding it to core, though.

The use case for ANY_VALUE is compliance with the standard.
--
Vik Fearing