Re: Subquery -> slowness

Jim,

you are correct: although sometimes the optimizer will refactor queries
with subqueries as joins, do not rely on it doing that in all the
cases.

Try this:

SELECT c.CustID,c.OtherInfo ,e.EventAmt,e.EventDt
FROM #Customer c JOIN #Event e ON c.CustID=e.CustID
JOIN
(SELECT MAX(EventDt) maxEventDt, CustID FROM #Event e group by CustID)
m ON c.CustID=e.CustID and .EventDt = m.maxEventDt
ORDER BY c.CustID

Good luck!

.