What is the ratio of professors and students?
professors refers to professor = 1; students refers to student = 1; ratio = divide(count(person.p_id) when professor = 1, count(person.p_id) when student = 1)
SELECT CAST(SUM(CASE  WHEN professor = 1 THEN 1 ELSE 0 END) AS REAL) * 100 / SUM(CASE  WHEN student = 1 THEN 1 ELSE 0 END) AS per FROM person
database name:db_id computer_student
course table course Cols: course id dtype integer, course level dtype text, 
person table person Cols: person ID dtype integer, professor dtype integer, student dtype integer, has position dtype text, in phase dtype text, years in program dtype text, 
advisedBy table advisedBy Cols: person id dtype integer, person id dummy dtype integer, 
taughtBy table taughtBy Cols: course ID dtype integer, person ID dtype integer, 
