How to store comma-separated values row by row in postgresql - sql

Question

Input:
('{"user":{"status":1,"loginid":1,"userids":{"userid":"5,6"}}}')
I want to insert into my table like this:
userid loginid status
---------------------------
5 1 1
6 1 1

Answer 1

Use regexp_split_to_table(). Assuming that the columns are integers:
with input_data(data) as (
values
('{"user":{"status":1,"loginid":1,"userids":{"userid":"5,6"}}}'::json)
)
-- insert into my_table(userid, loginid, status)
select
regexp_split_to_table(data->'user'->'userids'->>'userid', ',')::int as userid,
(data->'user'->>'loginid')::int as loginid,
(data->'user'->>'status')::int as status
from input_data
userid | loginid | status
--------+---------+--------
5 | 1 | 1
6 | 1 | 1
(2 rows)

Answer 2

Would be simpler with an array (JSON array) to begin with. The you can use json_array_elements_text(json). See:
How to turn json array into postgres array?
Convert the list you have to an array with string_to_array(). Then unnest().
SELECT unnest(string_to_array(js#>>'{user,userids,userid}', ',')) AS userid
, (js#>>'{user,loginid}')::int AS loginid
, (js#>>'{user,status}')::int AS status
FROM (
SELECT json '{"user":{"status":1,"loginid":1,"userids":{"userid":"5,6"}}}'
) i(js);
db<>fiddle here
I advise Postgres 10 or later for the simple form with unnest() in the SELECT list. See:
What is the expected behaviour for multiple set-returning functions in select clause?
I avoid regexp functions for simple tasks. Those are powerful, but substantially more expensive.