Schema: CREATE TABLE teaches (id VARCHAR, course_id VARCHAR); CREATE TABLE course (course_id VARCHAR, title VARCHAR); CREATE TABLE instructor (name VARCHAR, id VARCHAR)
Question: Find the name of the instructors who taught C Programming course before.
SQL: SELECT T1.name FROM instructor AS T1 JOIN teaches AS T2 ON T1.id = T2.id JOIN course AS T3 ON T2.course_id = T3.course_id WHERE T3.title = 'C Programming'