Want a cool Sig (9/4/2015)
Hi Luis, I've never seen this before and I don't see it in the online documentation... how does it work? I always thought you needed a date of some kind in the startdate argument same for the 0 in the DATEADD function... thanks, I'll remember this next time. 🙂
It's actually a very old trick. "0" is the "Date Serial Number" for 1900-01-01. The DATEDIFF counts the difference between that date and today's date in years (Year "boundaries", actually). The DATEADD adds those number of years back to 1900-01-01 to come up with the first date of this year, which is 2015-01-01.
A "Date Serial Number" is defined as "The number of days since midnight of 1900-01-01 for dates after that date and the number of days until 1900-01-01 (expressed as a negative number) for dates prior to that "0" date.
--Jeff Moden
Change is inevitable... Change for the better is not.