Full Outer Join

[tamilselvan]

Outer join is not supported by all RDBMS. Of course, Oracle supports one way outer join.
The other way of working is using NOT EXISTS.
Ex for one way outer join:
SELECT A.COL1, B.COL1
FROM A ,B
WHERE A.COL1 = B.COL1
UNION
SELECT A.COL1, ' '
FROM A
WHERE NOT EXISTS
(SELECT B.COL1 FROM B
WHERE A.COL1 = B.COL1);