SQL update datetime entries

Question

I have a table with a list of dates of datetime format in two columns.

Now what I would like to do is pull each non null date from Column1, add one year to each value and then store it into Column2.

So below, after the update, Column2 (the one with the nulls) will show:

2014-07-09 00:00:00.000 
2013-07-30 00:00:00.000 
2013-10-19 00:00:00.000 
2013-10-19 00:00:00.000

How does the syntax go? Do I need to do a select followed by an update?

Answer 1

You can use DATEADD

UPDATE YourTable
SET Column2 = DATEADD(YEAR, 1, Column1)
WHERE Column1 IS NOT NULL

Answer 2

UPDATE tbl
SET Column2 = DATEADD(year, 1, Column1)
WHERE Column2 IS NULL AND Column1 IS NOT NULL

That's gone to be ok