column reference "col_1" is ambiguous plpgsql - postgresql

Question

I'm writing postgresql function which inserts data and returns successfully inserted data rows.
The code is below.
CREATE OR REPLACE FUNCTION public.fn_insert_test(json_data jsonb)
returns table(col_1 varchar(255),
col_2 varchar(255),
col_3 timestamp)
LANGUAGE plpgsql
AS $function$
declare
--
begin
with my_table as (
with my_table1(my_json) as (
values(
json_data
)
)
insert into "test"(col_1, col_2, col_3)
select
elem->>'val1', elem->>'val2', now()
from
my_table1 t, jsonb_array_elements(my_json->'_data') elem
on conflict(col_1) do nothing
returning *
)
select * from my_table;
end
$function$
;
select fn_insert_test('{"_data": [{"val1":"1", "val2":"1"}, {"val1":"2", "val2":"2"}]}');
It occurs error below.
SQL Error [42702]: ERROR: column reference "col_1" is ambiguous
Detail: It could refer to either a PL/pgSQL variable or a table column.
Where: PL/pgSQL function fn_insert_test(jsonb) line 5 at SQL statement
[edit]

Answer 1

This is not the real problem here. There is a lot of problems in your code :
-> If you want to return a table, you have to use 'return query' : http://www.postgresqltutorial.com/plpgsql-function-returns-a-table/
-> I do not think you can use the WITH like you do: https://www.postgresql.org/docs/current/queries-with.html
Here is a functoinnal version of your code. But I am not quite sure of what you want :
CREATE OR REPLACE FUNCTION public.fn_insert_test(json_data jsonb)
returns table(col_1 varchar(255),
col_2 varchar(255),
col_3 timestamp)
LANGUAGE plpgsql AS
$$
declare
--json_data jsonb := '{"_data": [{"val1":"1", "val2":"1"}, {"val1":"2", "val2":"2"}]}';
begin
create temp table res (col_1 varchar (255), col_2 varchar (255), col_3 timestamp) on commit drop;
with my_table1(my_json) as
(
values(
json_data
)
)
, inserted as
(
insert into test(col_1, col_2, col_3)
select
elem->>'val1', elem->>'val2', now()
from
my_table1 t
, jsonb_array_elements(json_data->'_data') elem
on conflict do nothing
returning *
)
insert into res
select *
from inserted;
--raise notice '%', res_v;
return query select * from res;
end
$$
;
select fn_insert_test('{"_data": [{"val1":"1", "val2":"1"}, {"val1":"2", "val2":"2"}]}');