t...@sss.pgh.pa.us wrote: > I think we've spent a great deal of blood, sweat, and tears making that so, > or as nearly so as we could. We will in fact take any keyword after "AS", and > in recent versions many non-reserved keywords will work that way without "AS". > > (Mind you, I think the SQL spec made a serious design error in allowing "AS" > to be optional. But we have to live with that as best we can.)
Also, adrian.kla...@aklaver.com wrote: > Even reserved key words are not completely reserved in PostgreSQL, but can be > used as column labels (for example, SELECT 55 AS CHECK, even though CHECK is > a reserved key word): > https://www.postgresql.org/docs/current/sql-keywords-appendix.html Thank you both. I never would have guessed that a word with "reserved" status could be used as a column alias (with or without preceding it with AS). "not completely reserved in PostgreSQL" makes this sound like a PG special. So I was caught out yet again. And I fear that I'll continue to be caught out with other things—and maybe this one too, at some later date, when I've forgotten the present exchanges… Anyway, I believe that I have the answer to my question. And my new mental model allowed me to predict that, as presented, this would work: create function f() returns text language plpgsql as $body$ declare a constant int := 3; b constant int := 5; c constant int := 7; begin return a + b case /* + c */; end; $body$; select f(); It does! It predicted, too, that when "+ c" is uncommented, "create function" would fail with a syntax error. And that prediction also held out.
