jsonb_to_recordset() and json_to_recordset()

Purpose: Convert a homogeneous JSON array of JSON objects into the equivalent set of SQL records.

Signature For the jsonb variant:

input value:       jsonb
return value:      SETOF record

Notes: The function jsonb_to_recordset() bears the same relationship to jsonb_to_record() as jsonb_populate_recordset() bears to jsonb_populate_record().

Therefore, the DO block that demonstrated the functionality of jsonb_populate_recordset() can be extended to demonstrate the functionality of jsonb_to_recordset() as well and to show that their results are identical. See the "Record and array comparison" note in the account of jsonb_populate_recordset().

create type t as (a int, b int);

do $body$
  array_of_objects constant jsonb :=
      {"a": 1, "b": 2},
      {"b": 4, "a": 3},
      {"a": 5, "c": 6},
      {"b": 7, "d": 8},
      {"c": 9, "d": 0}

  rows_1 t[];
  rows_2 t[];
  expected_rows constant t[] :=
      (   1,    2)::t,
      (   3,    4)::t,
      (   5, null)::t,
      (null,    7)::t,
      (null, null)::t
  row t;
  n int := 0;
  for row in (
    select a, b
    from jsonb_populate_recordset(null::t, array_of_objects)
    n := n + 1;
    rows_1[n] := row;
  end loop;

  n := 0;
  for row in (
    select a, b
    from jsonb_to_recordset(array_of_objects)
    as on_the_fly(a int, b int)
    n := n + 1;
    rows_2[n] := row;
  end loop;

    (rows_1 = expected_rows) and
    (rows_2 = expected_rows),

The same considerations apply here as do for to jsonb_to_record() if the target record data type has a non-primitive field. The jsonb_to_recordset() syntax variant therefore has no practical advantage over the jsonb_populate_recordset() variant.