Re: [PATCH] Provide support for trailing commas

Greg Sabino Mullane <htamfids@gmail.com> writes:
> Happy New Year! Please find attached a patch to provide comprehensive
> trailing comma support, where we allow (when possible) a comma that does
> NOT come before the next item in a list. To wit:

> SELECT 1,2,3, FROM pg_class, ORDER BY greatest(relpages,1,);

Did we not discuss and reject this very idea in the past?
A quick search finds [1][2], and there may be more threads.

> This is not as trivial a task as it seems, as those who have dabbled with
> our parser (or parsers in general) may suspect.

Indeed.  I think it carries substantial risk of creating large parsing
problems down the road, when we try to integrate whatever random
syntax the SQL committee comes up with next.  And frankly, I don't
agree that it'd be beneficial.

                        regards, tom lane

[1] https://www.postgresql.org/message-id/flat/20140928114246.GA22150%40artax.karlin.mff.cuni.cz
[2] https://www.postgresql.org/message-id/flat/0368c60f-abe2-4f5f-972d-7cd1e6db2382%40gmail.com