From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Aleksander Alekseev <aleksander(at)timescale(dot)com> |
Cc: | pgsql-hackers(at)lists(dot)postgresql(dot)org, Viliam Ďurina <viliam(dot)durina(at)gmail(dot)com> |
Subject: | Re: MIN/MAX functions for a record |
Date: | 2024-03-22 15:12:55 |
Message-ID: | 906076.1711120375@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Aleksander Alekseev <aleksander(at)timescale(dot)com> writes:
>> In my queries I often need to do MIN/MAX for tuples, for example:
>> SELECT MAX(row(year, month))
>> FROM (VALUES(2025, 1), (2024,2)) x(year, month);
>> This query throws:
>> ERROR: function max(record) does not exist
>> Was this ever discussed or is there something preventing the implementation?
> I believe it would be challenging to implement max(record) that would
> work reasonably well in a general case.
As long as you define it as "works the same way record comparison
does", ie base it on record_cmp(), I don't think it would be much
more than a finger exercise [*]. And why would you want it to act
any differently from record_cmp()? Those semantics have been
established for a long time.
regards, tom lane
[*] Although conceivably there are some challenges in getting
record_cmp's caching logic to work in the context of an aggregate.
From | Date | Subject | |
---|---|---|---|
Next Message | Robert Haas | 2024-03-22 15:15:14 | Re: [DOC] Introducing Quick Start Guide to PL/pgSQL and PL/Python Documentation |
Previous Message | Fabrice Chapuis | 2024-03-22 15:05:43 | Re: hot updates and fillfactor |