Set calculated field to calculate specific records in Access

Question

I have a steering documents query, that has effective date and next revision date, I set the next revision date field to be calculated as after 2 years from the effective date: Next Revision Date: DateAdd("yyyy",2,[Effective Date]) However, some of these steering documents don't have a next revision date, only effective date, so I want these steering documents that start with WI to have null value on the next revision date, how can I do that?

Answer 1

That could be something like:

Next Revision Date: IIf(Left([DocumentName],2)="WI",Null,DateAdd("yyyy",2,[Effective Date]))