How to update postgresql json date field - json

Question

I am trying to update json date field with value from another column.
I am able to update with the following statement:
UPDATE table
SET column = column || '{"date_field":"2022-08-25"}'
where id = 123;
When I try to update with value from another column ie:
UPDATE table
SET json_column = json_column || '{"date_field":column}'
where id = 123;
I would get the following Error.
ERROR: invalid input syntax for type json
LINE 2: ...DATE table SET json_column = json_column || '{"date_field...
DETAIL: Token "column" is invalid.
CONTEXT: JSON data, line 1: {"date_field":column...
SQL state: 22P02
Character: 54
The database is PostgreSQL version 10.9.
Could someone point me to where I can find the right syntax?

Answer 1

Note || only works with jsonb.
\d json_test
Table "public.json_test"
Column | Type | Collation | Nullable | Default
-----------+---------+-----------+----------+---------
id | integer | | |
fld_json | json | | |
fld_jsonb | jsonb | | |
select fld_jsonb from json_test where id = 2;
fld_jsonb
----------------------
{"one": 1, "two": 2}
update json_test set fld_jsonb = fld_jsonb || jsonb_build_object('id', id) where id = 2 ;
UPDATE 1
select fld_jsonb from json_test where id = 2;
fld_jsonb
-------------------------------
{"id": 2, "one": 1, "two": 2}