SQL Get “ISO Year” for ISO Week

Question

I need to calculate the year a week is assigned to. For example the 29th december of 2003 was assigned to week one of year 2004 (this is only for europe, I think). You can t

Answer 1

This is the most compact solution I could come up with:

CASE
    WHEN DATEPART(ISO_WEEK, @Date) > 50 AND MONTH(@Date) = 1 THEN YEAR(@Date) - 1
    WHEN DATEPART(ISO_WEEK, @Date) = 1 AND MONTH(@Date) = 12 THEN YEAR(@Date) + 1
    ELSE YEAR(@Date) END

Can be used directly inside a SELECT statement. Or you could consider creating a user-defined function that takes the @Date parameter as input and outputs the result of the case statement.