Sharepoint DATE formula continued

With the following formula you can calculate how many days ago a date has expired:

=ALS(ISFOUT(DATEDIF(ALS(OC_Datum="";"1-1-3000";OC_Datum);VANDAAG;"d"));"NA";DATEDIF(OC_Datum;VANDAAG;"d"))

- The Dutch function DATUMVERSCHIL is not recognized by SharePoint. DATEDIF is.
- The words IFen IFERROR are not recognized, use the dutch notation.
- The test ALS(OC_Datum="";"1-1-3000";OC_Datum) is necessary to ascertain whether a date is filled or not.
If this is empty, a date far in the future is assumed, so not expired.
- If the date is in the future, the result is converted to NA. (or negative number of days) (may return empty("")