2010-10-20Myth: Oracle Cannot Index NULL

The source of this myth is rather easy to understand when you look at the correctly expressed statement:

The difference between the myth and the reality is small—it seems that they myth is a sloppy form of the truth.

The truth is that NULL can be indexed by adding another, not nullable, column to the index:

CREATE INDEX with_null ON table_name (nullable_column, '1');

Read Section 6.1 for the full story.