Consider the following relational schema:
teacher(ID, name, dept_name, salary, courseid, sec_id, semester, year)
What is the required relational expression for the query "To find the set of the courseid of all the courses taught in the Spring 2010 semester"?
1
\(Π_{courseid} (σ_{(semester="Spring")}(teacher))\)
2
\(Π_{teacher} (σ_{(semester="Spring" Λ year=2010)}(courseid))\)
3
\(Π_{courseid} (σ_{(semester="Spring" Λ year=2010)}(teacher))\)
4
\(σ_{courseid} (Π_{(semester="Spring" Λ year=2010)} (teacher))\)