Re: "RETURNING PRIMARY KEY" syntax extension

Greg Stark <stark@mit.edu> writes:
> On Thu, Jul 3, 2014 at 7:37 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> TBH, I thought that RETURNING PRIMARY KEY was already fairly iffy
>> in that the application would have little idea what it was getting back.
>> IF EXISTS would make it so spongy as to be useless, IMO.

> Seems easy enough to look at the count of columns in the result set.

Sure, if you know how many columns are in the table to begin with; but
that goes back to having table metadata.  If you don't, you're probably
going to be issuing "RETURNING *", and AFAICS "RETURNING *, PRIMARY KEY"
would be entirely useless (even without IF EXISTS :-().

I'm still unconvinced that there's a robust use-case here.
        regards, tom lane