How to remove an element in jsonb integer array in PostgreSQL - json

Question

On Postgres, in a table called "photo" I have a jsonb column called "id_us" containing a json integer array, simply like this one [1,2,3,4]
I would like to find the query to remove the element 3 for example.
The closer I could get is this
SELECT jsonb_set(id_us, ''
, (SELECT jsonb_agg(val)
FROM jsonb_array_elements(p.id_us) x(val)
WHERE val <> jsonb '3')
) AS id_us
FROM photo p;
Any idea how to solve this?
Thank you!

Answer 1

You can use a subquery containing JSONB_AGG() function while filtering out the index value 3(by starting indexing from 1) such as
WITH p AS
(
SELECT JSONB_AGG(j) AS js
FROM photo
CROSS JOIN JSONB_ARRAY_ELEMENTS(id_us)
WITH ORDINALITY arr(j,idx)
WHERE idx != 3
)
UPDATE photo
SET id_us = js
FROM p
Demo
Edit : If you need to remove the value but not index as mentioned in the comment, just use the variable j casted as numeric
WITH p AS
(
SELECT JSONB_AGG(j) AS js
FROM photo
CROSS JOIN JSONB_ARRAY_ELEMENTS(id_us)
WITH ORDINALITY arr(j,idx)
WHERE j::INT != 18
)
UPDATE photo
SET id_us = js
FROM p
Demo
P.S: using JSONB_SET(), the comma-seperated place for the removed element along with quotes will still remain in such a way that in the following
WITH p AS
(
SELECT ('{'||idx-1||'}')::TEXT[] AS idx
FROM photo
CROSS JOIN JSONB_ARRAY_ELEMENTS(id_us)
WITH ORDINALITY arr(j,idx)
WHERE j::INT = 18
)
UPDATE photo
SET id_us = JSONB_SET(id_us,idx,'""')
FROM p;
SELECT * FROM photo;
id_us
-----------------
[127, 52, "", 44]

Answer 2

I've run across a similar issue, and it stems from the - operator. This operator is overloaded to accept either text or integer, but acts differently for each type. Using text will remove by value, and using an integer will remove by index. But what if your value IS an integer? Well then you're shit outta luck...
If possible, you can try changing your jsonb integer array to a jsonb string array (of integers), and then the - operator should work smoothly.
e.g.
'{1,2,3}' - 2 = '{1,2}' -- removes index 2
'{1,2,3}' - '2' = '{1,2,3}' -- removes values == '2' (but '2' != 2)
'{"1","2","3"}' - 2 = '{"1","2"}' -- removes index 2
'{"1","2","3"}' - '2' = '{"1","3"}' -- removes values == '2'