Which of the query in SQL is an example of self-join? I. SELECT a.column_name FROM table1 a, table1 b WHERE a.x = b.x; II. SELECT b.column_name FROM table1 a, table2 b WHERE a.y = b.y;

Example: self join example

SELECT
    e.first_name + ' ' + e.last_name employee,
    m.first_name + ' ' + m.last_name manager
FROM
    sales.staffs e
INNER JOIN sales.staffs m ON m.staff_id = e.manager_id
ORDER BY
    manager;