Oracle Vs. SQL Server Computed / Virtual Columns

I was trolling around reading various articles and ran into the following link:

http://devcorner.georgievi.net/pages/database/oracle_database/oracle_tips/virtual-columns-oracle

In short, it goes into introducing a virtual column in Oracle 11g. I did not realize that this feature would be a new feature as I had been using something similar in SQL Server for some time to either create a placeholder column with a default value that would later be used or contain a computed value as a solution to a calculation that generates a value to be stored in that named field.

The question I have is, Lets say in SQL Server I do:

SELECT
     TableID,
     0 AS MyCustomColumnName
FROM TableName

In both Oracle and SQL Server, are these known as virtual columns or do they have different names between the 2 platforms? What are the differences between doing t his in either platform if any?

The article mentions:

You should keep in mind that:

virtual columns may not reference other virtual columns;
virtual columns only within the containing table. You cannot reference columns within other tables.

So that does that mean in a package in oracle where multiple stored procedures are created and ran, that one computed column value cannot be referenced from another stored procedure? I am interested in hearing about both platforms but my preference at this point in time leans more to the oracle side.