Re: idea: allow AS label inside ROW constructor

On 10/23/2014 09:57 AM, Florian Pflug wrote:
> 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.
>

Well, I think we need to see those other use cases. The only use case I 
recall seeing involves the already provided case of constructing JSON.

cheers

andrew