How to do an UPDATE in JSONB?

Question

PostgreSQL

The crux of the matter is as follows.
There is a test table with id and json fields. The json field of type jsonb contains entries in the json format:
{
"a" : 5,
"b" : 5,
"c" : 5
}
I can select data with
SELECT json->'s' FROM test WHERE id = 5;
How can UPDATE json->'s' = 6; be done?
How can I add a new key-value pair json->'d' = 5 to this object?

Answer 1

You will have to overwrite the value of the json field. To change "from" to 6:

UPDATE test
SET json = json || '{"c":6}'::jsonb
WHERE id = 5;

To add a new key:

UPDATE test
SET json = json || '{"d":5}'::jsonb
WHERE id = 5;