Example Queries Find the set of all courses taught in the Fall 2009 semester,and in the Spring 2010 semester (t3s e section (t [course_id ]=s [course_id s [semester]"Fall"^s [year]=2009 ^3u section (t [course_id ]u [course id u[semester]=“Spring”Au[year]=2010)} Find the set of all courses taught in the Fall 2009 semester,but not in the Spring 2010 semester {t|3s e section(t [course_id ]=s [course_id s [semester]="Fall"^s [year]=2009 ∧-3u∈section(t[course_id]=u[course_id]∧ u[semester]=“Spring”Au[year]=2010)} Database System Concepts-6th Edition 6.17 ©Silberschat乜，Korth and SudarshanDatabase System Concepts - 6 6.17 ©Silberschatz, Korth and Sudarshan th Edition Example Queries {t | s  section (t [course_id ] = s [course_id ]  s [semester] = “Fall”  s [year] = 2009  u  section (t [course_id ] = u [course_id ]  u [semester] = “Spring”  u [year] = 2010 )} Find the set of all courses taught in the Fall 2009 semester, and in the Spring 2010 semester {t | s  section (t [course_id ] = s [course_id ]  s [semester] = “Fall”  s [year] = 2009   u  section (t [course_id ] = u [course_id ]  u [semester] = “Spring”  u [year] = 2010 )} Find the set of all courses taught in the Fall 2009 semester, but not in the Spring 2010 semester