PET 2nd task completed

2026-02-17 15:08:15 +03:00
parent e67862e09c
commit 0c4ad4965d
1 changed files with 39 additions and 1 deletions
@@ -235,3 +235,41 @@ from viewed_count vc
 left join possible_lessons pl on vc.user_id = pl.user_id
 ;
 ------------------------------------------------------------------------------------------------------------------
 -- 2 задание Эффективность курсов
 create materialized view course_summary AS
 	with lessons_per_course as (
 								select c.id as course_id, c.title as course_title,
 								COUNT(distinct e.user_id) as unique_users,
 								COUNT(distinct l.id) as lessons_count
 								from courses c
 								left join enrollments e on c.id = e.course_id
 								join lessons l on e.course_id = l.course_id
 								group by c.id, c.title
 								),
 	course_views as (
 					select l.course_id, COUNT(lv.id) as total_views
 					from lesson_views lv
 					join lessons l on lv.lesson_id = l.id
 					group by l.course_id
 					),
 	view_date as (
 					select l.course_id,
 					MIN(lv.viewed_at) as first_viewed_at,
 					MAX(lv.viewed_at) as last_viewed_at
 					from lessons l
 					join lesson_views lv on l.id = lv.lesson_id
 					group by l.course_id
 					)
 	select lpc.course_id, lpc.course_title, lpc.unique_users, lpc.lessons_count,
 	ROUND(1.00 * cv.total_views / lpc.unique_users, 2) as avg_views_per_user,
 	vd.first_viewed_at,
 	vd.last_viewed_at
 	from lessons_per_course lpc
 	join course_views cv on lpc.course_id = cv.course_id
 	left join view_date vd on cv.course_id = vd.course_id
 	order by course_id
 ;