SQL to provide month/year vs. prev. month/year compares?

[pk400i]

HI I have to write a Report that will show groups such as Food products sold, e.g. Meat, Fish, others, etc.
comparing this year month with last year/month going back 4 months as well.

I was not sure if this is something you group on or how to set up such buckets here. My exisitng SQL is posted below. I wanted to setup my group totals there going from the previous month, i.e. if it ran today, we would start with April 2009 and April 2008, totaling the quotes field and then the same for 3 months prior on both years.

Thank you for any pointers and assistance.

 

[hmckillop]

an example may be

declare @v_Startdate datetime
select @v_StartDate = dateadd(mm,-3,getdate())
select [productid], [quantity], [value], convert(varchar,month(mydateField)) + convert(varchar,month(mydateField)) as yearmonth
from myTable
where
convert(varchar,month(mydateField)) + convert(varchar,month(mydateField)) >
convert(varchar,month(@v_StartDate )) + convert(varchar,month(@v_StartDate )) 

group by [productid],convert(varchar,month(mydateField)) + convert(varchar,month(mydateField))

not tested, and not even sure if it works

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