Platinum's product SQL-Station has an add-on called Plan Analyzer For Oracle (PAFO) that works quite nicely. I disagree that EXPLAIN PLAN is sufficient for optimizing SQL. Besides the fact that it is cumbersome to use and ugly, it, like most Oracle functionality, is useful only if you already know how to use it. With PAFO, all of your choices are laid out in front of you. You can easily paste in a statement and see the 3 main optimizer plans with little legends and help to explain what's going on. You can also add hints if you so choose, with explanations of what each hint does. You can then actually run the statements (safely, as DML is automatically rolled-back). It times them and gathers all the necessary statistics for you. You can then compare and contrast various plans from various viewpoints. Mind you, I am certainly not saying this is the end-all, be-all of tools, as it has its share of issues, not the least of which is that it leaks like the Titanic. But it beats the pants off of 'EXPLAIN PLAN by itself'.

- Chris