What is the Course Id for English
select course_id from courses where course_name = "English"
how many different student ids are there?
select count ( distinct student_id ) from student_course_attendance
How many students enrolled in Course ID 302?
select count ( * ) from courses as t1 join student_course_attendance as t2 on t1.course_id = t2.course_id where t2.course_id = 302