The most repeated suggestion you'll get: don't store calculations. Do that in forms/reports/queries. So no field anywhere for total years. That should be calculated as required, not stored. Maybe your form (or query or report) has a calculated field that uses IIF function. So subtract if there are 2 values, and show nothing if both values are not present. Your query calculated field could be (untested) TotalYears: IIF(IsNull(EndDate),Date-StartDate,StartDate-EndDate) but I would probably use DateDiff function instead so that I could get the time span in whatever value I wanted (subject to the values that DateDiff can return of course). You might want to Google DateDiff function. Note that spaces and special characters (save for underscore) or reserved words are not used by pros (or me, for that matter
). So EndDate, not End Date and no use of the word Date for my own objects.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.