Re: Finding "most recent" using daterange

On Wed, 22 May 2024 at 10:15, Greg Sabino Mullane <htamfids@gmail.com>
wrote:

> This is a good candidate for a window function. Also note that nulls
> already get sorted correctly by the DESC so no need to get 'infinity'
> involved, although you could write 'DESC NULLS FIRST' to be explicit about
> it.
>
> with x as (select *,  row_number() over (partition by id order by
> upper(dates) desc, lower(dates) desc) from example)
>   select id,value,dates from x where row_number = 1;
>

Don’t you need NULLS LAST for the lower bounds? There NULL means something
closer to -infinity and should appear after the non-NULL values in a
descending sort.

Actually it strikes me that this sorting issue could be a reason to avoid
NULL bounds on ranges and prefer the use of +/-infinity if the underlying
data type supports it.