CREATE FUNCTION opensips_cdrs_1_6() RETURNS TEXT
    LANGUAGE plpgsql
    AS $$
DECLARE   bye_record  INTEGER DEFAULT 0;
          v_callid varchar;
          v_from_tag varchar;
          v_to_tag varchar;
          v_inv_time TIMESTAMP;
          v_bye_time TIMESTAMP;
          inv_cursor CURSOR FOR SELECT TIME, callid, from_tag, to_tag FROM acc WHERE METHOD='INVITE' AND cdr_id='0';
          ROW RECORD;
BEGIN
  FOR ROW IN SELECT TIME, callid, from_tag, to_tag FROM acc WHERE METHOD='INVITE' AND cdr_id='