delete from
    TBL_EMPLOYEES
where
    SEX == "F"
    and (
        substr(BIRTHDAY, 1, 4) < "1980"
        or(
            substr(BIRTHDAY, 1, 4) == "1980"
            and substr(BIRTHDAY, 6, 2) < "08"
        )
        or(
            substr(BIRTHDAY, 1, 4) == "1980"
            and substr(BIRTHDAY, 6, 2) == "08"
            and substr(BIRTHDAY, 9, 2) <= "05"
        )
    )