postgres_json_example.sql

DROP TABLE IF EXISTS purchases;
CREATE TEMP TABLE purchases (
  data jsonb
);

INSERT INTO purchases (data)
VALUES ('{
  "purchase_id": 83577474,
  "customer_id": 173645,
  "items": [
    {
      "product_id": 76,
      "title": "beer",
      "price": 9.99,
      "quantity": 6
    },
    {
      "product_id": 90,
      "title": "pampers",
      "price": 545.60,
      "quantity": 2
    }
  ],
  "total_price": 1151.14
}
')
;

SELECT data->>'customer_id' AS customer_id 
FROM purchases
;

SELECT (jsonb_array_elements(data->'items')->>'title') AS title
FROM purchases
;