sql_mode=ORACLE: Make LPAD and RPLAD return NULL instead of empty string

SELECT

  CASE

    WHEN LPAD('a', 0) IS NULL THEN 'IS NULL'

    ELSE 'IS NOT NULL'

  END AS c

FROM DUAL;

C

-----------

IS NULL

SELECT

  CASE

    WHEN RPAD('a', 0) IS NULL THEN 'IS NULL'

    ELSE 'IS NOT NULL'

  END AS c

FROM DUAL;

C

-----------

IS NULL