On Mon, Oct 28, 2019 at 7:54 AM Isaac Morland <isaac.morl...@gmail.com> wrote: > Postgres already allows != as a synonym for <>. I think having =! mean > something subtly but significantly different is a terrible idea. At a minimum > we would have to remove the synonym, which would be a backwards compatibility > break.
I certainly agree with that. I do think, though, that IS DISTINCT FROM is a terribly verbose thing to have to write all the time. It's not that bad when you write a query that contains one instance of it, but I've both seen and written queries where you need to use it a bunch of times, and that can get really annoying. So I don't think adding an operator that means the same thing is a bad idea. I don't think == and !== would be crazy, for instance; Tom's statement that someone might already be using == in an extension doesn't persuade me, because (1) even if it's true it's likely to inconvenience only a very small percentage of users and (2) the same argument can be applied to any operator name and is more likely to apply to operator names that don't look like line noise, and I refuse to accept the idea that we should commit either to never adding new operators ever again, or the competing idea that any we do add should look like line noise. AFAICS, Tom's got the right idea about how to fix the pg_dump schema-qualification issue, and the idea of creating an operator notation is a separate and possibly harder problem. Whatever we need to add to the IS [NOT] DISTINCT FROM syntax for pg_dump can just be hard-coded, but I guess if we want new operators we'd have to run around and update all of our built-in data types and extensions, after the (not so easy) preliminary step of reaching agreement on how it should all work. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
