Re: [PATCH] rename column if exists

"David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
> On Friday, November 5, 2021, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> I'd be more willing to overlook that if a clear use-case had been
>> given, but AFAICS no concrete case has been offered.

> The use case is the exact same one for all of these - indempotence,

... except that, as I explained, it's NOT really idempotent.
It's a sort of half-baked idempotence, which is exactly the kind
of underspecification you complain about in your next sentence.
Do we really want to go there?

The perspective I'm coming from is that it's not terribly hard
to write whatever sort of conditional DDL you want using plpgsql
DO blocks, so it's not like we lack the capability. I think we
should only provide pre-fab conditional DDL for the most basic,
solidly-defined cases; and it seems to me that RENAME IF EXISTS
isn't solid enough.

regards, tom lane