Re: row_to_json(), NULL values, and AS

Neil Conway <neil(dot)conway(at)gmail(dot)com> writes:
> On Fri, Jun 15, 2018 at 7:53 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> (3) As it happens, the column interpretation is chosen when it's
>> ambiguous (cf ParseComplexProjection).
>>
>> I'm a bit hesitant to muck with this behavior, given that it's stood
>> for ~20 years. However, if we did want to touch it, maybe the right
>> thing would be to give up the absolutist position that f(x) and x.f
>> are exactly interchangeable. We could say instead that we prefer the
>> function interpretation if function syntax is used, and the column
>> interpretation if column syntax is used.

> Interesting! Your proposed change seems quite reasonable to me.

Here's a proposed patch for that. (It needs to be applied over the
fixes in <14497(dot)1529089235(at)sss(dot)pgh(dot)pa(dot)us>, which are unrelated but
touch some of the same code.) I didn't add any test cases yet,
but probably it's desirable to have one.

I wrote the doc change on the assumption that we'd sneak this into
v11, but if anyone doesn't want to do that, I'll add it to the next
commitfest instead.

regards, tom lane