What about something along these lines - I can never get the math to work
right on SELECT statements (I'd just run two, and do the math myself...)

(select count(*) from volhistory where type='STGNEW') - (select count(*)
from volhistory where usage='STGDELETE')  [that's a minus sign between the
two statements]

That's how many tapes went into pools, and came out of pools, through the
day.  If you assume that the DBBackups/Snapshots are a wash - the same
number expire as are created daily, you have how many tapes TSM used.  If
you do exports, backupsets, etc, you'll need to add statements to grab
those values as well.

Nick Cassimatis