PostgreSQL joining using JSONB with TypeORM - postgresql

Question

I have this SQL
CREATE TABLE product(id SERIAL PRIMARY KEY, name text, categories JSONB);
INSERT INTO product(name, categories) VALUES
('prouct1', '{"ids":[4,5]}'),
('prouct2', '{"ids":[5,6]}'),
('prouct3', '{"ids":[7]}');
CREATE TABLE category(id bigint, rootid bigint);
INSERT INTO category(id, rootid) VALUES
(1, null),
(2, null),
(3, null),
(4, 1),
(5, 2),
(6, 1),
(7, 3);
I want to make this query with TypeORM. But I have no idea how to make jsonb_array_elements_text(b.categories->'ids') pc(categoryid) ON TRUE part with the TypeORM.
SELECT p.id, p.name, p.categories
FROM product p
INNER JOIN jsonb_array_elements_text(b.categories->'ids') pc(categoryid) ON TRUE
INNER JOIN category c ON pc.categoryid = c.categoryid AND c.rootid = 1000;
Alternatively, I was trying another query. But it is too slow when I put jsonb_array_elements_text(categories->'ids'). Why it happen?
SELECT p.id, p.name, p.categories
FROM product p
INNER JOIN (SELECT id, jsonb_array_elements_text(categories->'ids') categoryid FROM product) pc ON p.id = pc.id
INNER JOIN category c ON pc.categoryid = c.categoryid AND c.rootid = 1000;

Answer 1

In PostgreSQL have additional index type GIN for JSON and JSONB types. For best performance, you must create an index for this JSON field.
For example:
CREATE INDEX product_category_json_index ON product USING gin (categories jsonb_path_ops);
And I wrote an alternative query for you:
select main.*, cat.* from
(
select p.*, jsonb_array_elements((categories->'ids'))::integer as category_id
from product p
) main
inner join examples.category cat on cat.id = main.category_id;
I want to get more detailed information, for these tables, if you know then please explain to me how many records in both tables (product and category)
I want to insert to my local tables sample data (same count) for testing and analyzing