Execute the ALTER TABLE ADD COLUMNS command to add the new column, specifying a default value, and use the GENERATED ALWAYS AS clause to define it as a generated column.

Create a new table with the CREATE TABLE command, including the generated column definition in the WITH clause, and then migrate all data from the old table to the new one.

First, update all existing rows in the table to set the value of the new column using the UPDATE command, then add the column as a generated column with the ALTER TABLE ADD COLUMNS command.

Use the MERGE command to insert or update rows with the new column values, followed by the ALTER TABLE ADD COLUMNS command to add the column as a generated column.