It can be done without using windowed function (so, will have better performance):
SELECT *
FROM @mySampleTable s
WHERE s.CaseID IN (SELECT CaseID
FROM @mySampleTable
GROUP BY CaseID
HAVING MAX(StudentID) != MIN(StudentID))
_____________________________________________
"The only true wisdom is in knowing you know nothing"
"O skol'ko nam otkrytiy chudnyh prevnosit microsofta duh!":-D
(So many miracle inventions provided by MS to us...)
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