It depends on your requirements here. Are you trying to do a permanent consolidation? If so, why this way? Are you trying to do a report, or some other data display only?
This structure should be:
tblStudent
StudentID
LastName
FirstName
etc
tblActivity
ActivityID
tblStudent_Activity
Student_ActivityID
StudentID
ActivityID
Querying this properly normalized structure would allow you to make meaningful reports without duplication of records, as in your current example. This structure would also allow you to create a query to find out haw many students are playing Hockey, for example, without having to worry about where in the string it was entered, and whether it was spelled correctly by whomever made the entry.
If you are serious about doing this concatenation within a table, it may require some coding. Check out this thread to get started:
http://p2p.wrox.com/topic.asp?TOPIC_...rms=medication
mmcdonal
Look it up at:
http://wrox.books24x7.com