Hi

How about

Code:
UPDATE TRX
SET Discipline='SBP'
WHERE EXISTS
(SELECT 'X'
FROM APPOINT, TRX
WHERE APPOINT."Date"=TRX."TreatmentDate"
AND APPOINT."Patient"=TRX."Patient"
AND APPOINT."Clinic" =1320
AND APPOINT."Type" IN (0,1,2)
AND APPOINT.ID = TRX.ID
);