On Thu, Oct 26, 2023 at 2:56 PM Bruce Momjian <bruce@momjian.us> wrote:
On Wed, Oct 25, 2023 at 10:34:10PM -0700, David G. Johnston wrote: > I would reword the existing note to be something like: > > The SQL Standard defines specific aggregates and their properties, including > which of DISTINCT and/or ORDER BY is allowed. Due to the extensible nature of > PostgreSQL it accepts either or both clauses for any aggregate.
Uh, is this something in my patch or somewhere else? I don't think PostgreSQL extensible is an example of syntax flexibility.
Note The ability to specify both DISTINCT and ORDER BY in an aggregate function is a PostgreSQL extension.
I am pointing out that the first sentence of the existing note above seems to be factually incorrect. I tried to make it correct - while explaining why we differ. Though in truth I'd probably rather just remove the note.
> We get enough complaints regarding "apparent ordering" that I would like to > add: > > As a reminder, while some DISTINCT processing algorithms produce sorted output > as a side-effect, only by specifying ORDER BY is the output order guaranteed.
Well, we need to create a new email thread for this and look at all the areas is applies to since this is a much larger issue.
I was hoping to sneak this one in regardless of the bigger picture issues, since this specific combination is guaranteed to output ordered presently.
