Re: plpgsql variable assignment not supporting distinct anymore

pá 22. 1. 2021 v 9:21 odesílatel <easteregg(at)verfriemelt(dot)org> napsal:

> hi,
>
> no noticed after the assignment with union (
> https://www.postgresql.org/message-id/flat/20210105201257.f0d76aff%40mail.verfriemelt.org
> ), that the assignment with distinct is broken aswell.
>
>
>
> DO $$
> DECLARE
> _test bool;
> BEGIN
>
> _test := DISTINCT a FROM ( VALUES ( (true), ( true ) ) )t(a);
>
> END $$;
>
> i would argue, that thats a way more common usecase than the union, which
> was merely bad code.
>

What is the sense of this code?

This is strange with not well defined behavior (in dependency on data type
the result can depend on collate).

More - because this breaks simple expression optimization (10x), then the
code will be significantly slower, than you use IF or CASE.

Regards

Pavel

> tested with version 14~~devel~20210111.0540-1~299.gitce6a71f.pgdg110+1
> from the apt repo
>
> with kind redards,
> richard
>