The DATEADD function returns wrong values.

[Chris123Terr]

Hello. I have a calendar table made with dax:

calendar= Calendar(min(Date), max(Date))

The calendar starts on 07/04/1996 and ends on 06/11/1998

Now. I am using the function:

ALL = Calculate(sum(column), dateadd(calendar[Date], -1, Year)

And it returns wrong values, but when I alter the calendar table so that it starts on 01/01/1996 and ends on 12/31/1998, it returns the correct values. Why does this happen?

[HotChilli]

Well, DATEADD is a function that returns a date (or strictly a set of dates) but those dates must already exist in the date table defined in the model, for example, if you have a date table which has dates 15/03/1992 to 20/03/1992 i.e. just 6 dates and you use a formula like DATEADD(Calendar[Dates], 4, DAY) then the results would be like this:

15/03/1992 ->19/03/1992

16/03/1992 ->20/03/1992

17/03/1992 -> Should be 21/03/1992 but will return blank as 21/03/1992 is not in the original dates table

18/03/1992 -> Should be 22/03/1992 but will return blank as 22/03/1992 is not in the original dates table

and so on

[HotChilli]

What are the wrong values?

The key point that catches a lot of people is that DATEADD can only return dates which already exist in the date table.

As the date table you have is quite limited, I suspect this is what's happening

[Chris123Terr]

What do you mean by? "DATEADD can only return dates which already exist in the date table."
Thanks