I'm taking it to mean that we need to "anchor" the #student table to return only a single version of each StudentID. With that in mind, will something like this work?

selecte.StudentID,

s.StudentKey,

e.SchoolID,

s.EnrolledSchoolKey,

e.EntryDate,

e.EntryCode,

e.WithDrawalDate,

e.WithDrawalCode

from #student s

join #enrollement e on s.enddate >= e.WithdrawalDate and s.StudentID = e.StudentID

where s.StudentID = '0082600'

and s.CurrentFlag = 1