The other, and maybe the main, reason for putting conditionals into the join is to make the query more efficient. If you blind join a table then all matching rows get included in intermediate results (within the server) only to be filtered out later on during the processing of the WHERE clause. I never understood that until I read some very excellent articles on how JOINS work right here on SQLServerCentral.com We were working on a query that just sucked and often timed out. We joined millions of transactions to thousands of customers only to filer that down to hundreds of results. Moving the conditional into the join then joins only those few hundred transactions to the customer set. One heck of performance boost. Check them out.