Select matching element from jsonb in Postgres - postgresql

Question

I have the the table orders which contains a column called stores with a jsonb with many elements like
id status stores
1 in progress [{"id": 1, "lat": 19.41, "lng": -99.18, "name": "Domino´s pizza condesa", "products": "3 tacos de cabeza"},
{"id": 2, "lat": 19.03, "lng": -99.9, "name": "Papa guapa roma", "products": "una papa"}]
1 done [{"id": 3, "lat": 19.44, "lng": -99.28, "name": "ABC", "products": "3 tacos de cabeza"},
{"id": 4, "lat": 19.23, "lng": -99.29, "name": "Papa guapa roma", "products": "una papa"}]
I want to query the table orders and select only the element from the json that matches {"lat:19.41", "lng":-99.18}
So I get something like
id status store_filtered
1 in progress [{"id": 1, "lat": 19.41, "lng": -99.18, "name": "Domino´s pizza condesa", "products": "3 tacos de cabeza"}]
I currently have
SELECT id, status, stores->0 AS stores_filtered FROM orders WHERE stores #> '[{"lat":19.41, "lng": -99.18}]'
But that 0 is what I need to make dynamic, to give me the element that matches not the first.

Answer 1

with r as (
select status, unnest(stores) as stores
from orders
)
select * from r where stores->lat='19.41' and stores->lng='-99.18'

Answer 2

Asssuming that you're using PostgreSQL 9.5 (or newer), you can use the jsonb_array_elements(json) (or jsonb_array_elements(json)) functions to "unnest" the array, and then choose.
For instance, you can try:
WITH orders(id, status, stores) AS
(
VALUES
(1, 'in progress',
'[{"id": 1, "lat": 19.41, "lng": -99.18, "name": "Domino´s pizza condesa", "products": "3 tacos de cabeza"},
{"id": 2, "lat": 19.03, "lng": -99.9, "name": "Papa guapa roma", "products": "una papa"}]'::jsonb),
(1, 'done',
'[{"id": 3, "lat": 19.44, "lng": -99.28, "name": "ABC", "products": "3 tacos de cabeza"},
{"id": 4, "lat": 19.23, "lng": -99.29, "name": "Papa guapa roma", "products": "una papa"}]')
)
, expanded_stores AS
(
SELECT
id, status, jsonb_array_elements(stores) AS single_store
FROM
orders
)
SELECT
id, status, single_store AS filtered_store
FROM
expanded_stores
WHERE
single_store #> '{"lat":19.41, "lng": -99.18}'
Or, assuming that you already have declared your orders table, you could just use:
SELECT
id, status, single_store AS filtered_store
FROM
(
SELECT
id, status, jsonb_array_elements(stores) AS single_store
FROM
orders
) AS expanded_stores
WHERE
single_store #> '{"lat":19.41, "lng": -99.18}' ;
You can check version 9.5 at http://rextester.com/MQE36487.
NOTE: Although this does work, it looks a bit "unnatural" for a SQL database. It is normally easier to normalize the information, and reserve JSON just where a lot of schema flexibility is really needed.