In 2 they show how to add virtual columns to an existing table, in 3 how to add indexes to existing virtual columns so they are pre-cooked. Like a cooking show.
Literally exactly as I meant it. I watch a lot of cooking shows, too, so this analogy holds up.
>In 2 they show how to add virtual columns to an existing table
No, in section 2 the table is created afresh. All 3 sections start with a CREATE TABLE.