delete 30 days from todays date?

I have a column that is to be updated to todays date - 30 days if it is older than that.

I tried this code but I get error for the conversion to datetime because it is out of range. Anyone have another solution?

update DATAFILE
set [Effective Date] = [Effective Date] - CAST('yyyy-mm-30' as datetime)
WHERE DATEDIFF ( dd , [Effective Date] , GetDate() ) >= 30update DATAFILE
set [Effective Date] = [Effective Date] - 30
WHERE DATEDIFF ( dd , [Effective Date] , GetDate() ) >= 30|||Ok, it was so simple?

I found this code worked also.

update DATAFILE
set [Effective Date] = DATEADD(dd, -30, GetDate())
WHERE DATEDIFF ( dd , [Effective Date] , GetDate() ) >= 30

The date is supposed to be updated to todays date minus 30 days.
Its ok now. Thanks...|||Do not use addition or subtraction operations on dates. SQL Server dates or not so simple as dates in other Microsoft products where you can just add or subtract whole numbers. I have gotten spurious results this way in the past.

Use the DATEADD and DATEDIFF functions instead.

blindman