Advanced Find query problem

Hi,

I have two campaigns, campaign A and campaign B

I'm trying to create a query that will give me accounts that are in campaign B, but not in campaign A.

If this was done in SQL, it would be something like this:

SELECT
a.accountid
FROM campaigns a
WHERE a.campaignname = "campaign A"
AND a.accountid NOT IN
(SELECT accountid FROM campaigns WHERE a.campaignname = "campaign B")

You can't do sub selects (IN or NOT IN) in CRM, so is there another way?