| From: | Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> |
|---|---|
| To: | Jeff Davis <pgsql(at)j-davis(dot)com> |
| Cc: | Isaac Morland <isaac(dot)morland(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: MERGE ... RETURNING |
| Date: | 2023-07-13 17:01:44 |
| Message-ID: | CAEZATCUHtYtBX5wVB4h8+06nMcTJat2DVhScG4EUHiTFRH7E+Q@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Thu, 13 Jul 2023 at 17:01, Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
>
> MERGE can end up combining old and new values in a way that doesn't
> happen with INSERT/UPDATE/DELETE. For instance, a "MERGE ... RETURNING
> id" would return a mix of NEW.id (for INSERT/UPDATE actions) and OLD.id
> (for DELETE actions).
>
Right, but allowing OLD/NEW.colname in the RETURNING list would remove
that complication, and it shouldn't change how a bare colname
reference behaves.
> The pg_merge_action() can differentiate the old and new values, but
> it's a bit more awkward.
>
For some use cases, I can imagine allowing OLD/NEW.colname would mean
you wouldn't need pg_merge_action() (if the column was NOT NULL), so I
think the features should work well together.
Regards,
Dean
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Dean Rasheed | 2023-07-13 17:30:59 | Re: MERGE ... RETURNING |
| Previous Message | Alvaro Herrera | 2023-07-13 16:54:13 | Re: remaining sql/json patches |