First of all, the article you are referring to neglect to mention one very important thing: The order of tables in the FROM clause might only influence the execution plan if the *rule based optimizer* (RBO) is used. Othervise (if the cost based optimizer (CBO) is used) the order of tables is totaly irrelevant. The only exception to this rule is if you use a hint /* + ORDERED*/ where usage of CBO is forced, however the order in which tables are processed in joins is explicitely suggested to the optimizer.

If you use RBO, then indeed the order of tables in FROM is relevant. The parcer processes the SQL statement "in the reverse order", meaning that tables in the FROM caluse will be processed from bottom up, right to left. So the table that is listed at the end of the list will be the driving table of the join. So in Tamilselvan's first example (the one without the hint) TabC will be processed first. However in the second example with the hint optimizer will very probably obey the suggestion and process the tables in the order as listed in the FROM clause, meaning that TabA will be processed first.

Once again: if you use CBO you generaly don't need to wory about the order of the tables in the FROM clause.