postgres upsert json props

Question

I'm not sure if this is possible or not, but I'm trying to get into the nitty gritty of what I can do in postgres 9.6.1 and this seems like maybe its possible. So given this table:

DROP TABLE IF EXISTS live_data;
CREATE TABLE live_data (
rec_id TEXT,
control_data JSONB
);
CREATE UNIQUE INDEX rec_id_idx ON live_data (rec_id);

I want to be able to upsert individual props on the control_data json without having to upsert a whole new json string.

With no rows in that table yet I tried this:

INSERT INTO live_data(rec_id, control_data) VALUES ('1', '{"set":{"some_prop": 99}}')
ON CONFLICT (rec_id) DO UPDATE SET control_data->'set'->'some_prop' = 99;

FWIW I get this error on that query :

syntax error at or near "->"

Am I writing that query wrong and/or is what I want to do just not currently possible?

Answer 1

Use jsonb_set():

INSERT INTO live_data(rec_id, control_data) 
VALUES ('1', '{"set":{"some_prop": 99}}');

INSERT INTO live_data(rec_id, control_data) 
VALUES ('1', '{"set":{"some_prop": 88}}')
ON CONFLICT (rec_id) DO 
UPDATE SET control_data = 
    jsonb_set(live_data.control_data, array['set','some_prop'], '88', true)
RETURNING *;

 rec_id |        control_data        
--------+----------------------------
 1      | {"set": {"some_prop": 88}}
(1 row)