On Thu, 2025-06-19 at 23:05 +0200, Phillip Diffley wrote: > Postgres has a to_jsonb function that will convert a value into its jsonb representation. > I am now trying to turn a json value back into its postgres type. I was hoping there would > be something like a from_jsonb function that, along with a type hint, could be used as an > inverse of to_jsonb, like > > from_jsonb(to_jsonb('{1,2,3}'::int[]) as int[] > > but I do not see a function like this. I was able to convert a json value back to its > postgres representation using the jsonb_to_record function, as used in the WHERE expression > below, but I feel like there might be a better way to do this. > > CREATE TABLE mytable (id int, col1 int[]); > INSERT INTO mytable VALUES (1, '{1, 2, 3}'), (2, '{3, 4, 5}'); > SELECT * from mytable WHERE col1 = (select col1 from json_to_record('{"col1": [1, 2, 3]}'::JSON) as x(col1 int[])); > > Is there a preferred method for turning a JSON value back to its postgres representation?
I think jsonb_populate_record() is the closest thing to what you envision.
jsonb_to_record avoids the temporary type.
select * from jsonb_to_record('{"ia":[1,2,3]}'::jsonb) as r (ia integer[]);
There is a gap for arrays. Scalars you can just cast and composites have these functions. But no simple/direct way to go from json array to sql array is presently implemented.
