How to update each json object in json array? - sql

Question

I have simple table table_b
id (integer)
data (json)
text (text)
1
{}
yes
2
{}
no
Json look like
{"types": [{"key": "first_event", "value": false}, {"key": "second_event", "value": false}, {"key": "third_event", "value": false}...]}
I just want to modify data and add to each json object in array ["test1", "test2"] to look like this :
{"types": [{"key": "first_event", "value": false, "can":["test1", "test2"] }, {"key": "second_event", "value": false , "can":["test1", "test2"]}, {"key": "third_event", "value": false , "can":["test1", "test2"]}...]}
ofcourse only where text like "yes"
I have tryed :
UPDATE table_b
SET data = jsonb_set(data , '{types,can}', '["test1", "test2"]'::jsonb, true)
where text like 'yes';
But it does not work. How can i loop over table_b and over data column?

Answer 1

The array value of a JSON object can be modified. It can be simply done by modifying the value present at a given index.

Answer 2

Using this sample data
create table table_b as
select * from (values
(1,'{"types": [{"key": "first_event", "value": false}, {"key": "second_event", "value": false}, {"key": "third_event", "value": false}]}'::jsonb,'yes'),
(2,'{}'::jsonb,'no'),
(3,'{"types": [{"key": "first_event", "value": false}]}'::jsonb,'yes')
) table_b(id,data,txt)
This query updates each array element, keeping the order in the ORDINALITY column
with table_b2 as (
select
id,item, index,
jsonb_set(item,('{"can"}')::TEXT[],'["test1", "test2"]') new_item
from table_b cross join
jsonb_array_elements(data -> 'types') WITH ORDINALITY arr(item, index)
where txt = 'yes')
select * from table_b2
|
id|item |index|new_item |
--+---------------------------------------+-----+------------------------------------------------------------------+
1|{"key": "first_event", "value": false} | 1|{"can": ["test1", "test2"], "key": "first_event", "value": false} |
1|{"key": "second_event", "value": false}| 2|{"can": ["test1", "test2"], "key": "second_event", "value": false}|
1|{"key": "third_event", "value": false} | 3|{"can": ["test1", "test2"], "key": "third_event", "value": false} |
3|{"key": "first_event", "value": false} | 1|{"can": ["test1", "test2"], "key": "first_event", "value": false} |
The next query concatenates the updated elements back to the array (keeping the right order) and performs a simple update
with table_b2 as (
select
id,item, index,
('{types,' || index - 1 || ',"can"}')::TEXT[] AS path,
jsonb_set(item,('{"can"}')::TEXT[],'["test1", "test2"]') new_item
from table_b cross join
jsonb_array_elements(data -> 'types') WITH ORDINALITY arr(item, index)
where txt = 'yes'),
table_b3 as (
select
id,
jsonb_agg(new_item order by index) new_data
from table_b2
group by id)
update table_b t
set data = table_b3.new_data
from table_b3
where t.id = table_b3.id
select * from table_b order by id;
id|data |txt|
--+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+---+
1|[{"can": ["test1", "test2"], "key": "first_event", "value": false}, {"can": ["test1", "test2"], "key": "second_event", "value": false}, {"can": ["test1", "test2"], "key": "third_event", "value": false}]|yes|
2|{} |no |
3|[{"can": ["test1", "test2"], "key": "first_event", "value": false}] |yes|