On Tue, May 31, 2016 at 4:34 PM, David Fetter <david@fetter.org> wrote:
Folks,
While querying some JSONB blobs at work in preparation for a massive rework of the data infrastructure, I ran into things that really puzzled me, to wit:
SELECT * FROM unnest('["a","b","c"]'::jsonb); ERROR: function unnest(jsonb) does not exist
SELECT * FROM jsonb_array_elements('["a","b","c"]'::jsonb); value ─────── "a" "b" "c" (3 rows)
I'd be inclined to -1 such a proposal. TIMTOWTDI is not a principle that we endeavor to emulate.
Having an overloaded form: <unnest(jsonb) : setof jsonb> is unappealing. While likely not that common the introduction of an ambiguity makes raises the bar considerably.
That said we do seem to be lacking any easy way to take a json array and attempt to convert it directly into a PostgreSQL array. Just a conversion is not always going to succeed though the capability seems worthwhile if as yet unasked for. The each->convert->array_agg pattern works but is likely inefficient for homogeneous json array cases.
