PET 2nd task fixed

aharlamcev/postgresql/Pet-projectsql.sql

@@ -237,7 +237,6 @@ 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,
@@ -249,26 +248,20 @@ create materialized view course_summary AS
 								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, 
+					COUNT(lv.id) as total_views,
 					MIN(lv.viewed_at) as first_viewed_at,
 					MAX(lv.viewed_at) as last_viewed_at
-					from lessons l
+					from lesson_views lv
-					join lesson_views lv on l.id = lv.lesson_id
+					join lessons l on lv.lesson_id = l.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,
+	cv.first_viewed_at,
-	vd.last_viewed_at
+	cv.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
 ;