The secret column type Snowflake refuses to document
Snowflake’s co-founders and chief architects, Benoit Dageville and Thierry Cruanes, spent many years working at Oracle. In fact, Oracle’s influence can be seen in many of the SQL constructs and functions that Snowflake supports. One such example is the concept of the virtual column.
Virtual columns straddle the line between physical and transformational modeling—between table and view. Virtual columns look like normal table columns, but their values are derived rather than stored on disc. They are an efficient way to embed simple business rules and transformational logic in a table without the overhead of maintaining views and incurring storage costs. Virtual columns can be defined through constants or transformational expressions such as the DEFAULT column operator. Strangely, they are not mentioned in the CREATE TABLE documentation at the time of writing (https://docs.snowflake.com/en/sql-reference/sql/create...
