SQL Subtract exactly a year

Question

First I want to thank everyone for helping me, It gave me a lot of ideas on how I should do this and I came up with my own method I just need help putting it into a query

Answer 1

OK... From your response to Joe Stefanelli, I think that part of what you are really trying to do is avoid having to rewrite the query each year. If that is the case, then you can create a numbers table. A simple and fast example would be like this...

 SELECT TOP 3000
        IDENTITY(INT,1,1) as N
   INTO #Numbers
   FROM Master.dbo.SysColumns sc1,
        Master.dbo.SysColumns sc2

Instant table with integers from 1 to 3000.

This allows you to join or subselect against the #Numbers table for your query. If you want to make a more limited range, then you can make a table with just the years you like (or a table valued function that will make the same table dynamically).

You could also take it a bit further and implement a table valued function that will return a two column result

year offset
2010 0    --Produced from DATEPART(y,GETDATE())
2009 -1    --loop/set subtract 1
2008 -2    --repeat until you have enough...

This way, your where clause could read something like

SELECT *
FROM yourTable, yourFunction
WHERE ((DYYYY = CAST(yourFunction.year as VARCHAR) AND (BOOKED <= DATEADD(yy, yourFunction.offset, GETDATE()))

Note that while the tv functions should save you a bit of maintenance programming each year, you may suffer some minor performance hits.