If you list a field for which the value is null, and there is
    a MISSING_VALUE clause for that field, Oracle Rdb supplies the
    missing value. If there is no MISSING_VALUE clause, and nulls are
    allowed, then Oracle Rdb supplies zeros for numeric fields, blanks
    for text fields, and the OpenVMS base date and time (17-NOV-1858
    00:00:00.00) for date fields.