SQL 1999 Syntax

SELECT table1.column, table2.column
FROM table1
[NATRUAL JOIN table2] |
[JOIN table2 USING (column_name)] |
[JOIN table2
  ON (table1.column_name = table2.column_name)] |
[LEFT | RIGHT | FULL OUTER JOIN table2
  ON (table1.column_name = table2.column_name)] |
[CROSS JOIN table2];

* To join n tables together, you need to have a minimum of n-1 join conditions.
** This ruls may not apply if your table has a concatenated primary key, in which case more than one column is required to uniquely indentify each row. 
   ==> Can anybody explain about this? If you can, please write a comment, please..

The SQL:1999-compliant join syntax does not offer any performance benefits over the Oracle-proprietary.

Oracle-proprietary joins  (8i and earlier release) :
  - equijoin
  - Non-equijoin
  - Outer join
  - Self-join

SQL:1999-compliant joins :
  - Cross join
  - Natural join
  - Using clause
  - Full (or two-side) outer join
  - Arbitrary join condition for outer join