Re: Sanding down some edge cases for PL/pgSQL reserved words

On Sat, Apr 26, 2025, at 05:10, Tom Lane wrote:
> "Joel Jacobson" <joel@compiler.org> writes:
>> For years, I've felt we could benefit from introducing convenience syntax to
>> explicitly require that exactly one row is affected by a query, something which
>> currently requires using a somewhat cumbersome workaround:
>
>> - Using `... INTO STRICT ...` for `SELECT`,
>> - Using `RETURNING ... INTO STRICT ...` for `DELETE/UPDATE/INSERT`, or
>> - Checking `ROW_COUNT` via `GET DIAGNOSTICS` and raising an error if not exactly one row.
>
>> I think it would be more convenient and intuitive if we could simply write:
>
>> ```
>> STRICT [SELECT | UPDATE | INSERT | DELETE] ...;
>> ```
>
> Meh.  I don't really have an opinion on whether this is worth bespoke
> syntax, but if it is:
>
> (1) I don't see why we'd restrict it to plpgsql as opposed to
> implementing it in core SQL.

Good point, I agree, that would be much better.

>
> (2) Putting the keyword at the front seems fairly un-SQL-like.
> For SELECT, "SELECT STRICT ..." would seem more natural, as it calls
> back to SELECT DISTINCT; or you could imagine integrating it into the
> LIMIT clause.  Not as sure what to do for the DML commands, but
> somewhere near where we put RETURNING seems saner.
>
> Also, even if we did do it in plpgsql exactly as you suggest, making
> it unreserved doesn't move the needle on whether that's possible.
> Most of plpgsql's statement-starting keywords are unreserved.
>
> But please, don't hijack this thread for that discussion ...

Understood, and thanks for clarifying this change doesn't affect the strictness idea.

/Joel