PostgreSQL | Add an auto-incrementing primary key to an existing table

postegre-auto-incremeting-primary-key-existing-table.md

MORDERN VERSIONS

   ALTER TABLE test1 ADD COLUMN id SERIAL PRIMARY KEY;

OLD VERSIONS

 ALTER TABLE test1 ADD COLUMN id INTEGER;
  CREATE SEQUENCE test_id_seq OWNED BY test1.id;
  ALTER TABLE test ALTER COLUMN id SET DEFAULT nextval('test_id_seq');
  UPDATE test1 SET id = nextval('test_id_seq');

https://stackoverflow.com/questions/2944499/how-to-add-an-auto-incrementing-primary-key-to-an-existing-table-in-postgresql