Update all values in a column with individual values I ran into a problem where Excel and SQL Server have different "zero day" date conventions, so that all the dates currently in one of my tables are two days ahead of where they should be. Is there an easy way to update all the dates?

I know I can do something like 

SELECT DatabaseID, P60_Date, DATEADD(day, -2, P60_Date) AS NEW_P60_Date FROM US_P60


But I don't know how to UPDATE all the values in P60_Date with the new dates.
It should be this simple: 

UPDATE u
SET u.P60_Date = DATEADD(DAY, -2, u.P60_Date)
FROM dbo.US_P60 AS u


If you want to be sure, you can do:

SELECT *
INTO dbo.US_P60_bk
FROM dbo.US_P60


Then validate the update is what you want. If it is, drop the _bk table.