Learn SQL Database Programming

Differences in RDMSes

Oracle only allows you to create virtual columns and does not allow you to add a column after a specific column, unlike in MySQL. You can create a virtual column in Oracle with the following code:

ALTER TABLE batting ADD batavg GENERATED ALWAYS AS (h/ab);

PostgreSQL only allows you to create a generated column in version 12 or higher. You can create a virtual generated column in PostgreSQL with the following code:

ALTER TABLE battingADD batavg numeric GENERATED ALWAYS AS (h/ab) VIRTUAL;

You can create a stored generated column in PostgreSQL with the following code:

ALTER TABLE battingADD batavg numeric GENERATED ALWAYS AS (h/ab) STORED;

SQL Server allows you to create a computed column but doesn't allow you to add ...