{ field-expr  }  { MISSING     }
    { record-expr }  { NOT MISSING }

    Specifies whether a field or record expression is null. The
    product using CDO evaluates a MISSING clause as true if the
    record or field expression is null.

    Specifies the name of a field or record in the database,
    consisting of a directory name or a field or record name and a
    context variable.

    When you use the keyword NOT, the product using CDO evaluates the
    clause as true if the record or field expression is not null.