The SQL query
SELECT columns
FROM TableA
RIGHT OUTER JOIN TableB
ON A.columnName = B.columnName
WHERE A.columnName IS NULL
Returns the following:
1
All rows in TableB, which meets equality condition above and, non from Table A which meets the condition
2
All rows in TableA, which meets equality condition above and none from Table B, which meets the condition
3
All rows in TableB, which meets equality condition
4
All rows in TableA, which meets equality condition