added Mater VIEW for Pet Project 'lesson_popularity_ranking'

2026-06-22 01:45:15 +05:00
parent 8495b6a66e
commit 6b22a048fc
1 changed files with 64 additions and 0 deletions
@@ -0,0 +1,64 @@
 CREATE MATERIALIZED VIEW lesson_popularity_ranking AS 
 SELECT 
 	pl.id AS lesson_id,
 	pl.title AS lesson_title,
 	pc.id AS course_id,
 	pc.title AS course_title,
 	total_views_lesson.total_views AS total_views,
 	table_unique_viewers.unique_v AS unique_viewers,
 	ROUND(AVG(views_one_user_per_one_lesson.views_per_viewer), 2) AS avg_views_per_viewer, --также это можно было посчитать total_views/unique_viewers
 	DENSE_RANK() OVER (
 		ORDER BY total_views_lesson.total_views DESC NULLS LAST
 	) AS popularity_rank,
 	ROUND(table_unique_viewers.unique_v * 100.0 / table_enrolled_users.enrolled_to_course, 2) || '%' AS completion_rate
 	FROM pet_lessons pl
 	LEFT JOIN (
 		SELECT 
 			lesson_id,
 			COUNT(*) AS total_views
 		FROM pet_lesson_views
 		GROUP BY lesson_id
 	) AS total_views_lesson
 		ON total_views_lesson.lesson_id = pl.id
 	LEFT JOIN pet_courses pc
 		ON pc.id = pl.course_id
 	LEFT JOIN (
 		SELECT
 			lesson_id,
 			COUNT(DISTINCT user_id) AS unique_v
 		FROM pet_lesson_views plv
 		GROUP BY plv.lesson_id
 	) AS table_unique_viewers
 		ON table_unique_viewers.lesson_id = pl.id
 	LEFT JOIN (
 		SELECT
 			lesson_id,
 			user_id,
 			COUNT(*) AS views_per_viewer
 		FROM pet_lesson_views plv
 		GROUP BY user_id, lesson_id
 		ORDER BY user_id, lesson_id
 	) AS views_one_user_per_one_lesson
 		ON views_one_user_per_one_lesson.lesson_id = pl.id
 	LEFT JOIN (
 		SELECT
 			course_id,
 			COUNT(DISTINCT user_id) AS enrolled_to_course
 		FROM pet_enrollments pe
 		GROUP BY course_id
 	) AS table_enrolled_users
 		ON table_enrolled_users.course_id = pc.id
 	GROUP BY pl.id, pl.title, pc.id, pc.title, total_views_lesson.total_views, table_unique_viewers.unique_v, table_enrolled_users.enrolled_to_course
 	ORDER BY lesson_id;