Which SQL statement is better in performance?
1. select * from emp e, dept d
   where e.dept_id=d.dept_id
   and d.dept_name='ACCOUNT'

2. select * from emp e, dept d
   where d.dept_name='ACCOUNT'
   and e.dept_id=d.dept_id

I don't think you will see any difference between these two queries. Generally speaking, the optimizer will evaluate WHERE predicates in whatever order it chooses, and in whatever order it thinks best. Even though one of the predicates is actually an old style, deprecated form of specifying a JOIN, and the other is a row selection, depending upon the presence of indexes and the distribution of data values these most likely will be processed in 'parallel', that is, more or less at the same time, while the JOIN results are being built.

You can inspect the query execution plan on your database to see if there is any difference between the two. My guess is that they will be identical.

Jeff Mason
Custom Apps, Inc.
www.custom-apps.com