Remove element from jsonb array - arrays

Question

I have the following jsonb. From the array pages I would like to remove the element called 'pageb'. The solutions offered in similar questions are not working for me.
'{
"data": {
"id": "a1aldjfg3f",
"pages": [
{
"type": "pagea"
},
{
"type": "pageb"
}
],
"activity": "test"
}
}'
My script right now looks like this. It doesnt return any error but the elements won't be removed.
UPDATE database
SET reports = jsonb_set(reports, '{data,pages}', (reports->'data'->'pages') - ('{"type":"pageb"}'), true)
WHERE reports->'data'->'pages' #> '[{"type":"pageb"}]';

Answer 1

The - operator cannot be applied here because the right-hand operand is a string defining a key, per the documentation:
Delete key/value pair or string element from left operand. Key/value pairs are matched based on their key value.
Removing a json object from a json array can be done by unpacking the array and finding the index of the object. A query using this method may be too complicated, so defining a custom function is very handy in this case.
create or replace function jsonb_remove_array_element(arr jsonb, element jsonb)
returns jsonb language sql immutable as $$
select arr- (
select ordinality- 1
from jsonb_array_elements(arr) with ordinality
where value = element)::int
$$;
And the update:
update my_table
set reports =
jsonb_set(
reports,
'{data,pages}',
jsonb_remove_array_element(reports->'data'->'pages', '{"type":"pageb"}')
)
where reports->'data'->'pages' #> '[{"type":"pageb"}]';
Working example in rextester.

Answer 2

The following is a combination of the answer provided for deleting an element inside an array reliably and the PostgreSQL's ability to use data-modifying WITH statements, but it needs an identity column (id in my test table) to work because of necessary correlation:
WITH new_reports AS (
SELECT
id,
reports #- array['data','pages',(position - 1)::text] AS new_value
FROM
test,
jsonb_array_elements(reports->'data'->'pages') WITH ORDINALITY arr(item, position)
WHERE
test.reports->'data'->'pages' #> '[{"type":"pageb"}]'
AND
item->>'type' = 'pageb'
)
UPDATE test SET reports = new_reports.new_value FROM new_reports WHERE test.id = new_reports.id;
The test data I used:
SELECT reports FROM test;
reports
-----------------------------------------------------------------------------------------------------
{"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}, {"type": "pagec"}], "activity": "test"}}
{"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}, {"type": "pageb"}], "activity": "test"}}
{"data": {"id": "a1aldjfg3f", "pages": [{"type": "pageb"}, {"type": "pagec"}], "activity": "test"}}
(3 rows)
...and after executing the query:
SELECT reports FROM test;
reports
-----------------------------------------------------------------------------------------------------
{"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}, {"type": "pagec"}], "activity": "test"}}
{"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagea"}], "activity": "test"}}
{"data": {"id": "a1aldjfg3f", "pages": [{"type": "pagec"}], "activity": "test"}}
(3 rows)
I hope that works for you.

Answer 3

There you go
do $$
declare newvar jsonb;
begin
newvar := jsonb '{ "customer": "John Doe", "buy": [{"product": "Beer","qty": 6},{"product": "coca","qty": 5}]}';
newvar := jsonb_set(newvar,'{buy}', jsonb_remove((newvar->>'buy')::jsonb,'{"product": "Beer"}'));
newvar := jsonb_set(newvar,'{buy}', jsonb_add((newvar->>'buy')::jsonb,'{"product": "cofe","qty": 6}'));
RAISE NOTICE '%', newvar;
end $$
create or replace function jsonb_remove(arr jsonb, element jsonb)
returns jsonb language sql immutable as $$
select ('['||coalesce(string_agg(r::text,','),'')||']')::jsonb from jsonb_array_elements(arr) r where r #> element=false
$$;
create or replace function jsonb_add(arr jsonb, element jsonb)
returns jsonb language sql immutable as $$
select arr||element
$$;