From 0fca2bcd7a0e588c21d0a6297d8707ef16ec7d06 Mon Sep 17 00:00:00 2001
From: Dmitry Medvedev <dmitri.medv15@gmail.com>
Date: Wed, 24 Jun 2026 15:50:06 +0500
Subject: [PATCH] added Mater VIEW 'conversion_funnel' in Pet Project

---
 .../11.6 Pet project Conversion_funnel.sql    | 152 ++++++++++++++++++
 1 file changed, 152 insertions(+)
 create mode 100644 dmedvedev/11.6 Pet project Conversion_funnel.sql

diff --git a/dmedvedev/11.6 Pet project Conversion_funnel.sql b/dmedvedev/11.6 Pet project Conversion_funnel.sql
new file mode 100644
index 0000000..1335254
--- /dev/null
+++ b/dmedvedev/11.6 Pet project Conversion_funnel.sql	
@@ -0,0 +1,152 @@
+CREATE MATERIALIZED VIEW conversion_funnel AS
+
+-- CTE какое кол-во человек записалось на курс 
+WITH 
+
+enrolled_users AS (
+	SELECT 
+		course_id,
+		COUNT(*) AS enrolled
+	FROM pet_enrollments pe
+	GROUP BY course_id
+),
+
+-- СТЕ на начавших смотреть курс
+started_users AS (
+	SELECT 
+		pc.id AS course_id,
+		COUNT(DISTINCT plv.user_id) AS started
+	FROM pet_courses pc
+	LEFT JOIN pet_lessons pl 
+		ON pc.id = pl.course_id
+	LEFT JOIN pet_lesson_views plv
+		ON plv.lesson_id = pl.id
+	GROUP BY pc.id
+),
+
+
+--СТЕ на кол-во просмотров курса и прогресс по курсу
+user_progress AS (
+	SELECT
+		pc.id AS course_id,
+		plv.user_id,
+		COUNT(DISTINCT lesson_id) AS count_views,
+		count_lesson_in_course.count_lesson_in_course AS count_lesson_in_course,
+		COUNT(DISTINCT lesson_id) * 1.0 / count_lesson_in_course AS progress
+	
+	FROM pet_courses pc
+
+	LEFT JOIN pet_lessons pl 
+		ON pl.course_id = pc.id
+
+	LEFT JOIN pet_lesson_views plv 
+		ON plv.lesson_id = pl.id
+
+	LEFT JOIN (
+		SELECT 
+			pl.course_id,
+			COUNT(*) AS count_lesson_in_course
+		FROM pet_lessons pl
+		GROUP BY pl.course_id
+	) AS count_lesson_in_course
+		ON count_lesson_in_course.course_id = pc.id
+
+
+	GROUP BY pc.id, plv.user_id, count_lesson_in_course
+	
+),
+
+main_table AS (
+	SELECT 
+		pc.id AS course_id,
+		pc.title AS course_title,
+		'registered' AS stage_name,
+		0 AS stage_order,
+		(SELECT COUNT(*) FROM pet_users pu) AS users_count,
+		ROUND(100, 2) || '%' AS conversion_from_previous,
+		ROUND(100, 2) || '%' AS conversion_from_start
+		
+	FROM pet_courses pc
+		
+	UNION ALL
+		
+	SELECT 
+		pc.id AS course_id,
+		pc.title AS course_title,
+		'enrolled' AS stage_name,
+		1 AS stage_order,
+		enrolled_users.enrolled,
+		ROUND(enrolled_users.enrolled * 100.0 / (SELECT COUNT(*) FROM pet_users pu), 2) || '%' AS conversion_from_previous,
+		ROUND(enrolled_users.enrolled * 100.0 / (SELECT COUNT(*) FROM pet_users pu), 2) || '%' AS conversion_from_start
+
+	FROM pet_courses pc
+	LEFT JOIN enrolled_users
+		ON enrolled_users.course_id = pc.id
+	
+	
+	UNION ALL
+		
+	SELECT 
+		pc.id AS course_id,
+		pc.title AS course_title,
+		'started' AS stage_name,
+		2 AS stage_order,
+		started_users.started,
+		ROUND(started_users.started * 100.0 / enrolled_users.enrolled, 2) || '%' AS conversion_from_previous,
+		ROUND(started_users.started * 100.0 / (SELECT COUNT(*) FROM pet_users pu), 2) || '%' AS conversion_from_start
+
+	FROM pet_courses pc
+	LEFT JOIN started_users
+		ON started_users.course_id = pc.id	
+	LEFT JOIN enrolled_users
+		ON enrolled_users.course_id = pc.id
+		
+	UNION ALL
+		
+	SELECT 
+		pc.id AS course_id,
+		pc.title AS course_title,
+		'mid_progress' AS stage_name,
+		3 AS stage_order,
+		(	SELECT COUNT(*) FROM user_progress
+			WHERE user_progress.course_id = pc.id AND user_progress.progress >= 0.5
+		),
+		ROUND((	SELECT COUNT(*) FROM user_progress
+				WHERE user_progress.course_id = pc.id AND user_progress.progress >= 0.5) * 100.0 / started_users.started, 2) || '%' AS conversion_from_previous,
+		ROUND((	SELECT COUNT(*) FROM user_progress
+				WHERE user_progress.course_id = pc.id AND user_progress.progress >= 0.5) * 100.0 / (SELECT COUNT(*) FROM pet_users pu), 2) || '%' AS conversion_from_start
+		
+	FROM pet_courses pc
+	LEFT JOIN started_users
+		ON started_users.course_id = pc.id	
+		
+		UNION ALL
+		
+	SELECT 
+		pc.id AS course_id,
+		pc.title AS course_title,
+		'completed' AS stage_name,
+		4 AS stage_order,
+		(	SELECT COUNT(*) FROM user_progress
+			WHERE user_progress.course_id = pc.id AND user_progress.progress >= 1),
+		ROUND((	SELECT COUNT(*) FROM user_progress 
+				WHERE user_progress.course_id = pc.id AND user_progress.progress >= 1) * 100.0 / 
+			(	SELECT COUNT(*) FROM user_progress
+				WHERE user_progress.course_id = pc.id AND user_progress.progress >= 0.5), 2) || '%' AS conversion_from_previous,
+		ROUND((	SELECT COUNT(*) FROM user_progress 
+				WHERE user_progress.course_id = pc.id AND user_progress.progress >= 1) * 100.0 / 
+				(SELECT COUNT(*) FROM pet_users pu), 2) || '%' AS conversion_from_start
+	FROM pet_courses pc
+	
+	ORDER BY course_id, stage_order
+)
+-- main select
+SELECT 
+	course_id,
+	course_title,
+	stage_name,
+	users_count,
+	conversion_from_previous,
+	conversion_from_start
+	
+FROM main_table;
\ No newline at end of file