Re: idea: allow AS label inside ROW constructor - Mailing list pgsql-hackers

From Florian Pflug
Subject Re: idea: allow AS label inside ROW constructor
Date
Msg-id FCA11004-4C08-4BE8-AEC4-A0F2F1325272@phlo.org
Whole thread Raw
In response to Re: idea: allow AS label inside ROW constructor  (Andrew Dunstan <andrew@dunslane.net>)
Responses Re: idea: allow AS label inside ROW constructor
List pgsql-hackers
On Oct23, 2014, at 15:39 , Andrew Dunstan <andrew@dunslane.net> wrote:
> On 10/23/2014 09:27 AM, Merlin Moncure wrote:
>> On Thu, Oct 23, 2014 at 4:34 AM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>>> postgres=# select row_to_json(row(10 as A, row(30 as c, 20 AS B) as x));
>>>          row_to_json
>>> ------------------------------
>>>  {"a":10,"x":{"c":30,"b":20}}
>>> (1 row)
>>>
>> wow -- this is great.   I'll take a a look.
>>
>
> Already in  9.4:
>
> andrew=# select json_build_object('a',10,'x',json_build_object('c',30,'b',20));
>           json_build_object
> ----------------------------------------
> {"a" : 10, "x" : {"c" : 30, "b" : 20}}
> (1 row)

> So I'm not sure why we want another mechanism unless it's needed in some other context.

I've wanted to name the field of rows created with ROW() on more than
one occasion, quite independent from whether the resulting row is converted
to JSON or not. And quite apart from usefulness, this is a matter of
orthogonality. If we have named fields in anonymous record types, we should
provide a convenient way of specifying the field names.

So to summarize, I think this is an excellent idea, json_build_object
non-withstanding.

best regards,
Florian Pflug




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