SQL Server deadlocks between select/update or multiple selects

Question

All of the documentation on SQL Server deadlocks talks about the scenario in which operation 1 locks resource A then attempts to access resource B and operation 2 locks reso

Answer 1

This can happen because a select takes a lock out on two different indexes, meanwhile an update takes a lock out on the same indexes in the opposite order. The select needs two indexes because the first index doesn't cover all of the columns it needs to access; the update needs two indexes because if you update an index's key column you need to take a lock on it.

http://blogs.msdn.com/bartd/archive/2006/09/25/770928.aspx has a fantastic explanation. Suggested fixes include adding an index that covers all of the columns the select needs, switching to snapshot isolation, or explicitly forcing the select to grab an update lock that it wouldn't normally need.