On Sat, Aug 29, 2015 at 3:39 PM, Tom Lane <[email protected]> wrote:
> Andrew Dunstan <[email protected]> writes: > > On 08/29/2015 08:47 AM, Shulgin, Oleksandr wrote: > >> Given there were no loud complaints about this, the current behavior > >> is appropriate for most users, the rest can still work around using > >> coalesce(to_json(...), json 'null'). > > > I don't think it's necessarily more correct. But I do agree that it's > > not a good idea to change the behaviour unless there is major > > unhappiness with it. > > I'm not entirely convinced that JSON NULL and SQL NULL should be treated > as the same concept, so I would say that the current behavior is fine --- > at least when you think about it in isolation. However, haven't we > already bought into that equivalence in these examples? > > regression=# select row_to_json(row(1,null,2)); > row_to_json > --------------------------- > {"f1":1,"f2":null,"f3":2} > (1 row) > > regression=# select array_to_json(array[1,null,2]); > array_to_json > --------------- > [1,null,2] > (1 row) > > or even in to_json itself: > > regression=# select to_json(array[1,null,2]); > to_json > ------------ > [1,null,2] > (1 row) > > The scalar case is definitely failing to be consistent with these. > Yes, that's my argument for correctness also: to_json() on a composite object should behave like distribution of to_json() calls over object/array elements. > Is consistency a sufficient reason to change it? > Not for me. -- Alex
