On Thursday, June 14, 2018, PG Bug reporting form <
noreply@postgresql.org> wrote:
The following bug has been logged on the website:
Bug reference: 15242
Logged by: David
Email address: david@daily-harvest.com
PostgreSQL version: 9.6.6
Operating system: Mac / DBeaver
Description:
I get this error: SQL Error [22023]: ERROR: cannot deconstruct an array as
an object
when running the statement below because the JSON_EACH function doesn't
recognize the JSON. If I remove the json_each function the query runs fine
and executes JSON_ARRAY_LENGTH on the same variable, even though both
functions take json.
WITH sample_text AS
(
SELECT TEXT '[{"id":11,"name":"Chocolate +
Blueberry","sku":"11-CHOBLU"},{"id":11,"name":"Chocolate +
Blueberry","sku":"11-CHOBLU"}]' AS txt
)
SELECT json_array_length(txt::json), json_each(txt::json) FROM sample_text
This is not a bug, nor is the behavior wrong.
json_each requires that the json being passed to it is a json object, not a json array. The docs and the error message say as much.
As json_each outputs two columns, one with the key and the other with the value, and since arrays don't have keys, it follows that json_each would be unable to operate on them.
David J.