Context: CREATE TABLE Courses (author_id VARCHAR, course_name VARCHAR); CREATE TABLE Course_Authors_and_Tutors (login_name VARCHAR, author_id VARCHAR)
Question: Find the login name of the course author that teaches the course with name "advanced database".
Answer: SELECT T1.login_name FROM Course_Authors_and_Tutors AS T1 JOIN Courses AS T2 ON T1.author_id = T2.author_id WHERE T2.course_name = "advanced database"