Condition within JOIN or WHERE

Question

Is there any difference (performance, best-practice, etc...) between putting a condition in the JOIN clause vs. the WHERE clause?

For example...

-- C         


        

Answer 1

Most RDBMS products will optimize both queries identically. In "SQL Performance Tuning" by Peter Gulutzan and Trudy Pelzer, they tested multiple brands of RDBMS and found no performance difference.

I prefer to keep join conditions separate from query restriction conditions.

If you're using OUTER JOIN sometimes it's necessary to put conditions in the join clause.