Complicated SQL Query... help?

I have 2 queries where I get the Subjects that someone is currently enrolled in and another where the query retrieves ALL the subjects. I am trying to present a list to the user of those classes they haven't signed up for yet:

I could do a MINUS operation to remove those classes they are already in, but I need to do a group by as well. Here is the query, maybe you can help. Thanks, Sean

Query :
SELECT ALL s.PERIOD, s.SUBJECT_DESCR,
po.ORDINALITY, s.SUBJECT_ID
FROM CTB.SUBJECT s, CTB.PERIODS_OFFERED po WHERE s.CONTRACT_ID=1
 AND (s.PERIOD=po.PERIOD
 AND s.CONTRACT_ID=po.CONTRACT_ID)
MINUS
(SELECT ALL s.PERIOD, s.SUBJECT_DESCR, po.Ordinality, s.SUBJECT_ID FROM CTB.SUBJECT s, CTB.USER_SUBJECT_ACCESS usa, CTB.PERIODS_OFFERED po WHERE usa.USERNAME='foo'
AND (usa.SUBJECT_ID=s.SUBJECT_ID)
AND (po.period = s.period)
)
GROUP BY s.PERIOD, s.SUBJECT_DESCR,
po.ORDINALITY, s.SUBJECT_ID
ORDER BY po.ORDINALITY ASC

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Before you buy. Received on Thu Oct 21 1999 - 13:02:27 CDT