Re: ANY_VALUE aggregate

On Mon, Dec 5, 2022 at 12:57 PM David G. Johnston <
david.g.johnston@gmail.com> wrote:

> On Mon, Dec 5, 2022 at 7:57 AM Vik Fearing <vik@postgresfriends.org>
> wrote:
>
>> The SQL:2023 Standard defines a new aggregate named ANY_VALUE.  It
>> returns an implementation-dependent (i.e. non-deterministic) value from
>> the rows in its group.
>>
>> PFA an implementation of this aggregate.
>>
>>
> Can we please add "first_value" and "last_value" if we are going to add
> "some_random_value" to our library of aggregates?
>
> 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.
>
> David J.
>

Adding to the pile of wanted aggregates: in the past I've lobbied for
only_value() which is like first_value() but it raises an error on
encountering a second value.