CREATE TABLE article (
    id      UUID PRIMARY KEY,
    properties JSONB NOT NULL
);

INSERT INTO article
VALUES (gen_random_uuid(), '{
  "price": 12.1,
  "name": "Kugelschreiber",
  "tags": {
    "manufacturer": "Siemens",
    "discounted": true
  }
}')

select 
  properties -> 'price' 
  properties ->> 'price' 
from article

SELECT *
FROM article
WHERE CAST(properties ->> 'price' AS NUMERIC) > 10

SELECT *
FROM article
WHERE properties -> 'tags' ? 'discounted'

SELECT *
FROM article
WHERE jsonb_exists(properties -> 'tags', 'discounted')

SELECT *
FROM article
WHERE properties -> 'tags' @> '{"manufacturer": "Siemens"}'