Querying nested hash of hashes using PostgreSQL - json

Question

I have a json datatype field to store complex data. JSON data looks like this hash:
{
"0" => {
"origin" => {},
"diff" => {
"type" => "type_1",
...
}
},
"1" => {
"origin" => {
"type" => "type_2",
...
},
"diff" => {
...
}
},
...
}
I've tried to transform json to array to avoid these index keys, but it did not help me.
WITH data_values AS (
SELECT id, array_to_json(array(SELECT t.v from json_each_text(data) as t(k,v))) as array_data
FROM event_logs
)
SELECT * FROM data_values
WHERE array_data->'origin'->>'type' = 'type_3' OR array_data->'diff'->>'type' = 'type_3'
Also, I had an idea to use json_object_keys and iterate over top-level keys to find the necessary key/value pair, but I'm a newbie to PSQL and I have some problems with solving that problem.
A version of PSQL is 11, so the JSON path is not available for me.
Table definition example:
CREATE TABLE event_logs (
id integer,
data json,
created_at timestamp without time zone
);
INSERT INTO event_logs (id, data)
VALUES
(1, '{"0": {"origin": {}, "diff": {"type": "type_1"}}, "1": {"origin": {"type": "type_1"}, "diff": {}}}'),
(2, '{"0": {"origin": {}, "diff": {"type": "type_2"}}, "1": {"origin": {}, "diff": {"type": "type_3"}}}'),
(3, '{"0": {"origin": {}, "diff": {"type": "type_3"}}, "1": {"origin": {"type": "type_2"}, "diff": {}}}')
Important note: there can be a different count of top-level keys.
I want to find records by the key/value pair (for example, type = 'type_3'). It should select records with ID 2 and 3.
Can you help me to do it right?

Answer 1

Storing the objects as an array instead of an integer-indexed object is a good idea, but that doesn't let you skip this level with the -> operators. (Only jsonpath can do that).
You will need to use the json_each iteration inside your WHERE clauses:
SELECT * FROM data_values
WHERE EXISTS(
SELECT *
FROM json_each(data)
WHERE value->'origin'->>'type' = 'type_3'
OR value->'diff'->>'type' = 'type_3'
);
(If you had used an array, json_each would become json_array_elements).