Finding the next occurrence of a given date with MS Access query - sql

Question

I'm currently working on a database that stores software licensing information such as software name, purchase date, cost, quantity, etc... After the software has been owned for 12 months, we must pay a maintenance fee.
My question therefore, is how to design a query that will take the purchase date and compute the next occurrence of that date to be stored in the maintenance date field. Ex) If a license was purchased on 12/31/1999, I would need to pay maintenance on 12/31/2016.
I don't have a lot of experience with MS Access or SQL queries, and after researching this for a while, I am not even sure this is possible. I would appreciate any help you guys could give me!

Answer 1

Here's a function that will do exactly this:
Public Function DateNextAnnualDay( _
ByVal AnnualDay As Date) _
As Date
Dim SomeDate As Date
Dim NextAnnualDay As Date
Dim Years As Integer
SomeDate = Date
NextAnnualDay = AnnualDay
Years = DateDiff("yyyy", AnnualDay, SomeDate)
If Years < 0 Then
' Don't calculate hypothetical annual days.
Else
NextAnnualDay = DateAdd("yyyy", Years, AnnualDay)
If DateDiff("d", SomeDate, NextAnnualDay) <= 0 Then
' Next annual day falls earlier in the year than SomeDate.
NextAnnualDay = DateAdd("yyyy", Years + 1, AnnualDay)
End If
End If
DateNextAnnualDay = NextAnnualDay
End Function

Answer 2

Here is the syntax
SELECT DateAdd("yyyy",1,[MyDate]) AS MaintDate
FROM Table;

Answer 3

If you need to do more complicated querying you can write a function in a module and then access it in a query using VBA. For instance you can iterate through a loop to match a condition
Function GetNextDate(ByVal dteOriginalDate As Date) As Date
While dteOriginalDate <= DateTime.Now
dteOriginalDate = DateAdd("Yyyy", 1, dteOriginalDate)
Wend
GetNextDate = dteOriginalDate
End Function
Will iterate adding one year from the original date to the point at which the date is in the future. You can the build it into a query (using right-click -> build) so that each row runs through your code and applied the logic.
This will allow you to store the original licence date in your database and calculate the next due date without having to know (or amend) the intervening years.