Whats the difference between alter table and update/set?

Question

Whats the difference between those commands? Its not doing the same thing?

Answer 1

`ALTER TABLE` changes the table structure, for example you can add a new column called `homeAddress` to your `phoneBook` table.
(This affects every row in the table, past, present and future!)

`UPDATE` updates individual rows. You can change every Marcus to Joseph for example. But you can not add new columns.
It's more like a `DELETE FROM` or even a `SELECT`.

Answer 2

Oh now i understand it much better, thank you so much!