Re: Make foo=null a warning by default.

> On Mon, Nov 26, 2018 at 9:19 PM Dmitry Dolgov <9erthalion6(at)gmail(dot)com> wrote:
>
> > On Tue, Aug 7, 2018 at 11:19 PM Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> >
> > On Mon, Jul 16, 2018 at 11:37:28AM -0400, Tom Lane wrote:
> > > Heikki Linnakangas <hlinnaka(at)iki(dot)fi> writes:
> > > > On 16/07/18 18:10, Tom Lane wrote:
> > > >> TBH I'm not really excited about investing any work in this area at all.
> > > >> Considering how seldom we hear any questions about transform_null_equals
> > > >> anymore[1], I'm wondering if we couldn't just rip the "feature" out
> > > >> entirely.
> > >
> > > > Yeah, I was wondering about that too. But Fabien brought up a completely
> > > > new use-case for this: people learning SQL. For beginners who don't
> > > > understand the behavior of NULLs yet, I can see a warning or error being
> > > > useful training wheels. Perhaps a completely new "training_wheels=on"
> > > > option, which could check may for many other beginner errors, too, would
> > > > be better for that.
> > >
> > > Agreed --- but what we'd want that to do seems only vaguely related to
> > > the existing behavior of transform_null_equals. As an example, we
> > > intentionally made transform_null_equals *not* trigger on
> > >
> > > CASE x WHEN NULL THEN ...
> > >
> > > but a training-wheels warning for that would likely be reasonable.
> > >
> > > For that matter, many of the old threads about this are complaining
> > > about nulls that aren't simple literals in the first place. I wonder
> > > whether a training-wheels feature that whined *at runtime* about null
> > > WHERE-qual or case-test results would be more useful than a parser
> > > check.
> >
> > I will again say I would love to see this as part of a wholesale
> > "novice" mode which warns of generally bad SQL practices. I don't see
> > this one item alone as sufficiently useful.
>
> Valid point. Maybe then at least we can outline what kind of bad SQL practices
> could be included into this "novice mode" to make it sufficiently useful?
> Otherwise this sounds like a boundless problem.

Due to lack of response I'm marking this as returned with feedback. Of course
feel free to resubmit it.