postgresql gtip noktalı çevir

create or replace function fn_getGtipNoktali(p_gtip varchar)
returns varchar
language plpgsql
as $$
declare
   temp_gtip varchar;
   ret_gtip varchar;
begin

SELECT replace(p_gtip, '.', '') into temp_gtip;	

select SUBSTRING ( temp_gtip ,0 , 5 )||'.'||SUBSTRING ( temp_gtip ,5 , 2 )||'.'||SUBSTRING ( temp_gtip ,7 , 2 )||'.'||SUBSTRING ( temp_gtip ,9 , 2 )||'.'||SUBSTRING ( temp_gtip ,11 , 2 ) into ret_gtip;

  return ret_gtip;
end;$$