CREATE TABLE Course_Authors_and_Tutors (address_line_1 VARCHAR2, author_id VARCHAR2)
CREATE TABLE Courses (author_id VARCHAR2, course_name VARCHAR2)

Find the addresses of the course authors who teach the course with name 'operating system' or 'data structure'.
SELECT T1.address_line_1 FROM Course_Authors_and_Tutors AS T1 JOIN Courses AS T2 ON T1.author_id = T2.author_id WHERE T2.course_name = "operating system" OR T2.course_name = "data structure"
SELECT "T1"."address_line_1" FROM "Course_Authors_and_Tutors" "T1" JOIN "Courses" "T2" ON "T1"."author_id" = "T2"."author_id" AND ("T2"."course_name" = "data structure" OR "T2"."course_name" = "operating system")