Convert Timestamp to ISO-8601 Date format (YYYYMMDD)

ts_to_isodate.sql

drop function if exists transformation_utils.ts_to_isodate (p_timestamp timestamp);
create or replace function transformation_utils.ts_to_isodate (p_timestamp timestamp)
  returns integer AS
$body$ 
declare 
    d  integer;
begin
    select to_char(p_timestamp::timestamp, 'YYYYMMDD') into d;
    return d;
end;
$body$
  language 'plpgsql';