JSON queries in PostgreSQL 9.6 - json

Question

presumed the following data:
select * from orderlist ;
id | orders | orderenvelope_id
----+--------------------------------------------+------------------
14 | { +| 13
| "orders" : [ { +|
| "orderType" : "OfferPurchaseOrder", +|
| "duration" : 1494413009450, +|
| "currencyCode" : "EUR" +|
| }, { +|
| "orderType" : "CustomerCreationOrder",+|
| "customerData" : { +|
| "customerType" : "PERSONAL_ACCOUNT",+|
| "contactData" : { +|
| "contactQuality" : "VALID", +|
| "firstName" : "Peter", +|
| "lastName" : "Pan" +|
| } +|
| } +|
| } ] +|
| } |
I want to get the 'OfferPurchaseOrder'; therefore the following SELECT was used:
select id, orderenvelope_id, o from orderlist list, json_array_elements(list.orders->'orders') as o where o->>'orderType' = 'OfferPurchaseOrder';
id | orderenvelope_id | o
----+------------------+-----------------------------------------
14 | 13 | { +
| | "orderType" : "OfferPurchaseOrder",+
| | "duration" : 1494413009450, +
| | "currencyCode" : "EUR" +
| | }
It looks as if works like a charm, only one thing: I want to integrate with Hibernate, so the colum should be named 'orders' instead of 'o' (as it was in the initial select); otherwise Hibernate will not be able to map the things properly.
Aside of this, the 'reduced' JSON-list should be in there, so the desired result should look like this:
id | orderenvelope_id | orders |
----+------------------+----------------------------------------+
14 | 13 | "orders" : [{ +
| | "orderType" : "OfferPurchaseOrder",+
| | "duration" : 1494413009450, +
| | "currencyCode" : "EUR" +
| | } +
| |]
Any hints?
Thx and regards
el subcomandante

Answer 1

If you can move to jsonb type than query can looks like:
WITH x AS (
SELECT id, orderenvelope_id, o
FROM orderlist list, jsonb_array_elements(list.orders->'orders') as o
WHERE o->>'orderType' = 'OfferPurchaseOrder'
)
SELECT id, orderenvelope_id, jsonb_set('{}'::jsonb, '{orders}'::text[], jsonb_agg(o))
FROM x
GROUP BY 1,2
;
However, if you can't use jsonb just cast text to json:
WITH x AS (
SELECT id, orderenvelope_id, o
FROM orderlist list, json_array_elements(list.orders->'orders') as o
WHERE o->>'orderType' = 'OfferPurchaseOrder'
)
SELECT id, orderenvelope_id, ('{"orders": ' || json_agg(o) ||'}')::json
FROM x
GROUP BY 1,2
;