dmedvedev/11.2 Pet project Effective courses.sql

@@ -79,5 +79,4 @@ LEFT JOIN first_viewed_at fva ON fva.id = pc.id
 LEFT JOIN last_viewed_at lva ON lva.id = pc.id 
 
 GROUP BY pc.id, uu.unique_users, lc.lesson_count, tv.total_views, first_viewed_at, last_viewed_at
-ORDER BY course_id
-
+ORDER BY course_id;

dmedvedev/11.3 Pet project platform_summary.sql

@@ -0,0 +1,20 @@
+CREATE MATERIALIZED VIEW platform_summary AS
+
+WITH stats AS (
+	SELECT 
+		(SELECT COUNT(*) total_users FROM pet_users pu) AS total_users,
+		(SELECT COUNT(*) total_courses FROM pet_courses pc) AS total_courses,
+		(SELECT COUNT(*) total_lessons FROM pet_lessons pl) AS total_lessons,
+		(SELECT COUNT(DISTINCT user_id) FROM pet_lesson_views plv) AS users_with_views,
+		(SELECT COUNT(*) FROM pet_lesson_views plv) AS total_views
+)
+
+SELECT
+	total_users,
+	total_courses,
+	total_lessons, 
+	users_with_views,
+	
+	ROUND((total_lessons * 1.0 / total_courses), 2) AS avg_lessons_per_course,
+	ROUND((total_views * 1.0 / total_lessons), 2) AS avg_views_per_lesson
+FROM stats;