Hmm, yeah, I would think that would give you a lot of old customers, since there's no "recent sale date" requirement. Maybe you need something more along these lines...?
FROM [EES_App].[dbo].[coitem] as new1
ship_date >= DATEADD(DAY, -7, CAST(GETDATE() AS date)) AND
NOT EXISTS( SELECT * FROM [EES_App].[dbo].[coitem] as new2
where new1.co_cust_num = new2.co_cust_num
and ship_date >= DATEADD(month,-12,GETDATE()) AND ship_date < DATEADD(DAY, -7, CAST(GETDATE() AS date)) )
SQL DBA,SQL Server MVP(07, 08, 09) Prosecutor James Blackburn, in closing argument in the Fatal Vision murders trial: "If in the future, you should cry a tear, cry one for them [the murder victims]. If in the future, you should say a prayer, say one for them. And if in the future, you should light a candle, light one for them."