убрал : из папок

2026-05-28 18:00:56 +03:00
parent e0b74cdc13
commit f045be8a39
30 changed files with 0 additions and 0 deletions
@@ -0,0 +1,45 @@
+--DROP TABLE IF EXISTS users;
+CREATE TABLE users (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	name varchar(100) NOT NULL,
+	age SMALLINT,
+	email varchar(100),
+	registration_date timestamptz NOT NULL
+);
+
+--DROP TABLE IF EXISTS courses;
+CREATE TABLE courses (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	title varchar(150) NOT NULL,
+	category varchar(50),
+	created_at timestamptz NOT NULL
+);
+
+--DROP TABLE IF EXISTS lessons;
+CREATE TABLE lessons (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	course_id bigint NOT NULL,
+	title varchar(150) NOT NULL,
+	duration_min SMALLINT NOT NULL,
+	FOREIGN KEY (course_id) REFERENCES courses(id)
+);
+
+--DROP TABLE IF EXISTS enrollments;
+CREATE TABLE enrollments (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	user_id bigint NOT NULL,
+	course_id bigint NOT NULL,
+	enrolled_at timestamptz NOT NULL,
+	FOREIGN KEY (user_id) REFERENCES users(id),
+	FOREIGN KEY (course_id) REFERENCES courses(id)
+);
+
+--DROP TABLE IF EXISTS lesson_views;
+CREATE TABLE lesson_views (
+	id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+	user_id bigint NOT NULL,
+	lesson_id bigint NOT NULL,
+	viewed_at timestamptz NOT NULL,
+	FOREIGN KEY (user_id) REFERENCES users(id),
+	FOREIGN KEY (lesson_id) REFERENCES lessons(id)
+);
@@ -0,0 +1,155 @@
+INSERT INTO users (name, age, email, registration_date) VALUES
+('Alice',25,'alice@mail.com','2023-01-10'),
+('Bob',30,'bob@gmail.com','2023-02-05'),
+('Charlie',22,'charlie@mail.com','2023-02-20'),
+('Diana',28,'diana@mail.com','2023-03-01'),
+('Ethan',35,'ethan@gmail.com','2023-03-10'),
+('Frank',29,'frank@mail.com','2023-01-05'),
+('Grace',26,'grace@gmail.com','2023-01-12'),
+('Henry',32,'henry@mail.com','2023-01-20'),
+('Iris',24,'iris@gmail.com','2023-02-10'),
+('Jack',27,'jack@mail.com','2023-04-15'),
+('Kelly',23,'kelly@gmail.com','2023-04-20'),
+('Leo',31,'leo@mail.com','2023-01-15'),
+('Mia',26,'mia@gmail.com','2023-01-18'),
+('Nina',28,'nina@mail.com','2023-01-08'),
+('Oscar',33,'oscar@gmail.com','2023-01-10'),
+('Paul',29,'paul@mail.com','2023-02-15'),
+('Quinn',24,'quinn@gmail.com','2023-03-20'),
+('Rita',27,'rita@mail.com','2023-04-01'),
+('Sam',30,'sam@gmail.com','2023-04-10'),
+('Tina',25,'tina@mail.com','2023-04-18');
+
+INSERT INTO courses (title, category, created_at) VALUES
+('SQL для начинающих','data','2023-01-01'),
+('Python для анализа данных','programming','2023-01-15'),
+('BI с нуля','business','2023-03-01'),
+('Excel для аналитиков','business','2023-02-01'),
+('Основы машинного обучения','data','2023-03-15');
+
+INSERT INTO lessons (course_id, title, duration_min) VALUES
+(1,'SELECT и FROM',10),
+(1,'JOIN',15),
+(1,'WHERE и фильтрация',12),
+(1,'Агрегации и GROUP BY',18),
+(1,'Подзапросы',25),
+(2,'Pandas основы',20),
+(2,'NumPy',15),
+(2,'Визуализация данных',22),
+(3,'Основы BI',12),
+(3,'Метрики и дашборды',18),
+(3,'Power BI введение',20),
+(4,'Формулы в Excel',15),
+(4,'Сводные таблицы',18),
+(4,'Графики и диаграммы',14),
+(5,'Введение в ML',20),
+(5,'Линейная регрессия',30),
+(5,'Классификация',28),
+(5,'Кластеризация',25);
+
+INSERT INTO enrollments (user_id, course_id, enrolled_at) VALUES
+(1,1,'2023-01-15'),
+(1,2,'2023-02-01'),
+(2,1,'2023-01-20'),
+(3,2,'2023-03-05'),
+(4,3,'2023-04-01'),
+(6,1,'2023-01-06'),
+(6,2,'2023-01-10'),
+(6,4,'2023-02-05'),
+(7,1,'2023-01-13'),
+(7,3,'2023-03-10'),
+(8,1,'2023-01-22'),
+(8,2,'2023-01-22'),
+(8,3,'2023-01-22'),
+(9,4,'2023-02-12'),
+(10,1,'2023-04-16'),
+(11,2,'2023-04-21'),
+(12,1,'2023-01-16'),
+(13,2,'2023-01-19'),
+(13,4,'2023-02-20'),
+(14,1,'2023-01-09'),
+(14,2,'2023-01-09'),
+(14,3,'2023-01-09'),
+(14,4,'2023-02-01'),
+(14,5,'2023-03-20'),
+(15,1,'2023-01-11'),
+(15,3,'2023-03-05'),
+(16,2,'2023-02-16'),
+(16,4,'2023-02-16'),
+(17,3,'2023-03-22'),
+(17,5,'2023-03-25'),
+(18,1,'2023-04-02'),
+(19,1,'2023-04-11'),
+(19,2,'2023-04-11'),
+(20,2,'2023-04-19'),
+(5,5,'2023-03-20'),
+(1,4,'2023-02-10'),
+(2,3,'2023-03-15'),
+(3,1,'2023-02-25'),
+(4,2,'2023-03-10'),
+(6,3,'2023-03-08'),
+(7,2,'2023-02-01'),
+(9,1,'2023-02-15'),
+(12,3,'2023-03-10'),
+(15,2,'2023-02-01'),
+(18,4,'2023-04-05');
+
+INSERT INTO lesson_views (user_id, lesson_id, viewed_at) VALUES
+(1,1,'2023-01-16 10:00:00'),
+(1,2,'2023-01-16 10:15:00'),
+(1,3,'2023-01-17 09:00:00'),
+(1,4,'2023-01-17 09:30:00'),
+(1,4,'2023-01-17 11:00:00'),
+(1,4,'2023-01-18 10:00:00'),
+(1,6,'2023-02-02 14:00:00'),
+(1,12,'2023-02-15 10:00:00'),
+(1,13,'2023-02-15 10:30:00'),
+(2,1,'2023-01-21 09:00:00'),
+(2,9,'2023-03-16 10:00:00'),
+(2,10,'2023-03-16 10:30:00'),
+(3,6,'2023-03-06 12:00:00'),
+(3,1,'2023-02-26 11:00:00'),
+(3,2,'2023-02-26 11:20:00'),
+(4,9,'2023-04-02 10:00:00'),
+(4,10,'2023-04-03 10:00:00'),
+(4,6,'2023-03-12 14:00:00'),
+(4,7,'2023-03-13 09:00:00'),
+(5,15,'2023-03-21 10:00:00'),
+(5,16,'2023-03-22 11:00:00'),
+(6,1,'2023-01-07 10:00:00'),
+(6,2,'2023-01-07 10:15:00'),
+(6,3,'2023-01-08 09:00:00'),
+(6,4,'2023-01-08 09:30:00'),
+(6,5,'2023-01-09 10:00:00'),
+(6,6,'2023-01-11 14:00:00'),
+(6,7,'2023-01-12 10:00:00'),
+(6,8,'2023-01-13 11:00:00'),
+(6,12,'2023-02-06 09:00:00'),
+(6,13,'2023-02-06 09:30:00'),
+(6,14,'2023-02-07 10:00:00'),
+(6,9,'2023-03-09 11:00:00'),
+(7,1,'2023-01-14 10:00:00'),
+(7,2,'2023-01-14 10:20:00'),
+(7,3,'2023-01-15 09:00:00'),
+(7,9,'2023-03-11 14:00:00'),
+(7,10,'2023-03-11 14:30:00'),
+(9,12,'2023-02-13 10:00:00'),
+(9,13,'2023-02-13 10:30:00'),
+(9,1,'2023-02-16 11:00:00'),
+(12,1,'2023-01-17 10:00:00'),
+(12,2,'2023-01-17 10:20:00'),
+(12,1,'2023-04-10 11:00:00'),
+(12,3,'2023-04-10 11:30:00'),
+(12,9,'2023-03-12 10:00:00'),
+(13,6,'2023-01-20 14:00:00'),
+(13,7,'2023-01-21 10:00:00'),
+(13,12,'2023-02-21 09:00:00'),
+(14,1,'2023-01-09 08:00:00'),
+(14,2,'2023-01-09 08:15:00'),
+(14,3,'2023-01-10 10:00:00'),
+(14,4,'2023-01-10 10:30:00'),
+(14,5,'2023-01-11 09:00:00'),
+(14,6,'2023-01-10 14:00:00'),
+(14,7,'2023-01-11 10:00:00'),
+(14,8,'2023-01-12 11:00:00'),
+(14,9,'2023-01-10 08:00:00');
@@ -0,0 +1,40 @@
+CREATE MATERIALIZED VIEW user_cohort_analysis AS
+WITH users_and_enrollments_results AS (
+	SELECT
+		date_trunc('month', u.registration_date)::date AS cohort_month,
+		count(DISTINCT u.id) AS users_in_cohort,
+		count(DISTINCT e.user_id) AS enrolled_users,
+		count(DISTINCT e.course_id) courses_in_cohort
+	FROM
+		users u
+	JOIN
+		enrollments e ON u.id = e.user_id
+	GROUP BY
+		cohort_month
+),
+lesson_views_results AS (
+	SELECT
+		date_trunc('month', u.registration_date)::date AS cohort_month,
+		count(DISTINCT lv.user_id) AS active_users,
+		round(avg(lv.viewed_at::date - u.registration_date::date), 0) AS avg_time_to_first_view
+	FROM
+		users u
+	LEFT JOIN
+		lesson_views lv ON u.id = lv.user_id
+	GROUP BY
+		cohort_month	
+)
+SELECT
+	uer.cohort_month,
+	uer.users_in_cohort,
+	uer.enrolled_users,
+	lvr.active_users,
+	round((lvr.active_users / uer.users_in_cohort::numeric) * 100, 2) || '%' AS retention_rate,
+	round(uer.courses_in_cohort / uer.users_in_cohort::numeric, 2) AS avg_courses_per_user,
+	lvr.avg_time_to_first_view
+FROM
+	users_and_enrollments_results uer
+JOIN
+	lesson_views_results lvr ON uer.cohort_month = lvr.cohort_month
+ORDER BY
+	uer.cohort_month;
@@ -0,0 +1,114 @@
+CREATE MATERIALIZED VIEW conversion_funnel AS
+WITH stage_courses AS (
+	-- registered
+	(SELECT
+		0 AS course_id,
+		1 AS stage_id,
+		'registered' AS stage_name,
+		count(DISTINCT u.id) AS users_count
+	FROM
+		users u)
+	UNION ALL
+	-- enrolled
+	(SELECT
+		e.course_id,
+		2 AS stage_id,
+		'enrolled' AS stage_name,
+		count(DISTINCT e.user_id) AS users_count
+	FROM
+		enrollments e
+	GROUP BY
+		e.course_id
+	ORDER BY
+		e.course_id)
+	UNION ALL	
+	-- started
+	(SELECT
+		l.course_id,
+		3 AS stage_id,
+		'started' AS stage_name,
+		count(DISTINCT lv.user_id) AS users_count
+	FROM
+		lessons l
+	JOIN
+		lesson_views lv ON l.id = lv.lesson_id
+	GROUP BY
+		l.course_id
+	ORDER BY
+		l.course_id)
+	UNION ALL
+	-- mid_progress
+	(WITH lessons_mid AS (
+		SELECT
+			l.course_id,
+			ceil(percentile_cont(0.5) WITHIN GROUP (ORDER BY l.id)) AS mid_in_lesson_id
+		FROM
+			lessons l
+		GROUP BY
+			l.course_id
+	)
+	SELECT
+		lm.course_id,
+		4 AS stage_id,
+		'mid_progress' AS stage_name,
+		count(lv.user_id) AS users_count
+	FROM
+		lessons_mid lm
+	LEFT JOIN
+		lesson_views lv ON lm.mid_in_lesson_id = lv.lesson_id
+	GROUP BY
+		lm.course_id, lm.mid_in_lesson_id
+	ORDER BY
+		lm.course_id)
+	UNION ALL
+	-- completed
+	(WITH courses_lessons_id AS (
+		SELECT
+			l.course_id,
+			l.id AS lesson_id
+		FROM
+			lessons l
+		GROUP BY
+			l.course_id, l.id
+	),
+	lessons_numbers AS (
+		SELECT
+			cli.course_id,
+			cli.lesson_id,
+			ROW_NUMBER() OVER(PARTITION BY cli.course_id ORDER BY cli.lesson_id DESC) AS lesson_number
+		FROM
+			courses_lessons_id cli
+	)
+	SELECT
+		ln.course_id,
+		5 AS stage_id,
+		'completed' AS stage_name,
+		count(lv.user_id) AS users_count
+	FROM
+		lessons_numbers ln
+	LEFT JOIN
+		lesson_views lv ON ln.lesson_id = lv.lesson_id
+	WHERE
+		ln.lesson_number = 1
+	GROUP BY
+		ln.course_id, ln.lesson_id
+	ORDER BY
+		ln.course_id)
+)
+SELECT
+	sc.course_id,
+	c.title AS course_title,
+	sc.stage_name,
+	sc.users_count,
+	CASE
+		WHEN lag(sc.users_count) OVER (PARTITION BY sc.course_id ORDER BY sc.stage_id) IS NULL THEN 'first stage'
+		WHEN lag(sc.users_count) OVER (PARTITION BY sc.course_id ORDER BY sc.stage_id) = 0 THEN 0::text || '%'
+		WHEN lag(sc.users_count) OVER (PARTITION BY sc.course_id ORDER BY sc.stage_id) IS NOT NULL THEN round((sc.users_count / lag(sc.users_count) OVER (PARTITION BY sc.course_id ORDER BY sc.stage_id)::NUMERIC) * 100, 0)::text || '%'
+	END AS conversion_from_previous,
+	round((sc.users_count / FIRST_VALUE(sc.users_count) OVER (ORDER BY sc.stage_id)::NUMERIC) * 100, 0)::text || '%' AS conversion_from_start
+FROM
+	courses c
+RIGHT JOIN
+	stage_courses sc ON c.id = sc.course_id
+ORDER BY
+	sc.course_id;
@@ -0,0 +1,41 @@
+CREATE MATERIALIZED VIEW course_summary AS
+WITH courses_unique_users AS (
+	SELECT
+		e.course_id,
+		count(e.user_id) AS unique_users
+	FROM
+		enrollments e
+	GROUP BY
+		e.course_id
+),
+lessons_results AS (
+	SELECT
+		l.course_id,
+		count(distinct l.id) AS lessons_count,
+		count(lv.lesson_id) AS total_views,
+		min(lv.viewed_at)::date AS first_viewed_at,
+		max(lv.viewed_at)::date AS last_viewed_at
+	FROM
+		lessons l
+	LEFT JOIN
+		lesson_views lv ON l.id = lv.lesson_id
+	GROUP BY
+		l.course_id
+)
+SELECT
+	c.id AS course_id,
+	c.title AS course_title,
+	cuu.unique_users,
+	lr.lessons_count,
+	lr.total_views,
+	round(lr.total_views / cuu.unique_users::numeric, 2) AS avg_views_per_user,
+	lr.first_viewed_at,
+	lr.last_viewed_at
+FROM
+	courses c
+JOIN	
+	courses_unique_users cuu ON c.id = cuu.course_id
+JOIN
+	lessons_results lr ON c.id = lr.course_id
+ORDER BY
+	c.id;
@@ -0,0 +1,39 @@
+CREATE MATERIALIZED VIEW lesson_popularity_ranking as
+WITH lesson_views_results AS (
+	SELECT
+		lv.lesson_id,
+		count(lv.user_id) AS total_views,
+		count(DISTINCT lv.user_id) AS unique_viewers
+	FROM
+		lesson_views lv
+	GROUP BY
+		lv.lesson_id
+),
+enrollments_results AS (
+	SELECT
+		e.course_id,
+		count(e.user_id) AS enrolled_to_course
+	FROM
+		enrollments e
+	GROUP BY
+		e.course_id
+)
+SELECT
+	l.id AS lesson_id,
+	l.title AS lesson_title,
+	c.title AS course_title,
+	lvr.total_views,
+	lvr.unique_viewers,
+	round(lvr.total_views / lvr.unique_viewers::numeric, 2) AS avg_views_per_viewer,
+	dense_rank() OVER (ORDER BY lvr.total_views desc) AS popularity_rank,
+	round((lvr.unique_viewers / er.enrolled_to_course::numeric) * 100, 0) || '%' AS completion_rate
+FROM
+	lessons l
+JOIN
+	courses c ON l.course_id = c.id
+JOIN
+	lesson_views_results lvr ON l.id = lvr.lesson_id
+JOIN
+	enrollments_results er ON c.id = er.course_id
+ORDER BY
+	popularity_rank;
@@ -0,0 +1,48 @@
+CREATE MATERIALIZED VIEW platform_summary as
+WITH users_count AS (
+	SELECT
+		count(*) AS total_users
+	FROM
+		users
+),
+courses_count AS (
+	SELECT
+		count(*) AS total_courses
+	FROM
+		courses
+),
+lessons_count AS (
+	SELECT
+		count(*) AS total_lessons
+	FROM
+		lessons
+),
+users_with_views AS (
+	SELECT
+		count(distinct user_id) AS users_with_views
+	FROM
+		lesson_views
+),
+views_count AS (
+	SELECT
+		count(*) AS total_views
+	FROM
+		lesson_views lv
+)
+SELECT
+	uc.total_users,
+	cc.total_courses,
+	lc.total_lessons,
+	uwv.users_with_views,
+	round(lc.total_lessons / cc.total_courses::NUMERIC, 2) AS avg_lessons_per_course,
+	round(vc.total_views / lc.total_lessons::NUMERIC, 2) AS avg_views_per_lesson
+FROM
+	users_count uc
+CROSS JOIN
+	courses_count cc
+CROSS JOIN
+	lessons_count lc
+CROSS JOIN
+	users_with_views uwv
+CROSS JOIN
+	views_count AS vc;
@@ -0,0 +1,24 @@
+CREATE MATERIALIZED VIEW user_activity_summary AS
+SELECT
+	u.id AS user_id,
+	u.name,
+	count(DISTINCT e.course_id) AS enrollment_count,
+	count(DISTINCT lv.lesson_id) AS viewed_lessons_count,
+	max(lv.viewed_at)::date AS last_view,
+	min(lv.viewed_at)::date AS first_view,
+	((count(DISTINCT lv.lesson_id)::numeric(5,2) / count(DISTINCT l.id)) * 100)::numeric(5, 2) AS engagement_rate
+FROM
+	users u
+JOIN
+	enrollments e ON u.id = e.user_id
+JOIN
+	courses c ON e.course_id = c.id
+JOIN
+	lessons l ON c.id = l.course_id
+LEFT JOIN
+	lesson_views lv ON u.id = lv.user_id -- сюда - 'AND l.id = lv.lesson_id'
+GROUP BY
+	u.id, u.name
+ORDER BY
+	u.id;
+-- Кинул его в нейронку на проверку, она сказала что надо добавить 'AND l.id = lv.lesson_id' при присоединении таблицы lesson_views(сделал пометку в коде), это нужно чтобы точно проверить, что урок который посмотрел пользователь точно принадлежит его курсу, чтобы избежать ошибок из-за некорректных данные если такие появятся в результате какого либо сбоя или ошибки.
@@ -0,0 +1,51 @@
+-- Задание 1
+SELECT
+	*
+FROM
+	conversion_funnel
+WHERE
+	stage_name = 'started'
+ORDER BY
+	conversion_from_previous;
+-- Первые 2 курса, гже отавлилось больше всего учеников между этапами enrolled → started
+
+
+-- Задание 2
+SELECT
+	*
+FROM
+	lesson_popularity_ranking lpr
+WHERE
+	lpr.avg_views_per_viewer > 1
+LIMIT 3;
+
+
+-- Задание 3
+SELECT
+	*
+FROM
+	user_cohort_analysis uca
+ORDER BY
+	retention_rate DESC;
+-- Не разобрался как можжно соеденить с другими таблицам
+-- А retention_rate такой, наверное потому что при запуске курсов была пиар компания большая, и делали рассылки с напоминанием позаниматься, а потом перестали, вот и удержание похерилось
+
+
+-- Задание 4
+-- Витрина - user_activity_summary
+-- Всяко разно попробовал подобавлять индексы, итог: без индексов быстрее. Просмотрел весь запрос, вроде ничего не нужно менять - лишнего ничего нет.
+
+-- Витрина - course_summary
+-- Тут также как и в предидущем - и так и сяк попробовал, план запроса не меняется, время не улучшается
+
+-- Витрина - platform_summary
+-- Тут тоже нечего менять - всё из CROSS JOIN. Попробовал вместо count(*) писать count(id) думал мол в ширину будет меньше читать, в итоге выяснил что и так и так одинаково читает
+
+-- Витрина - user_cohort_analysis
+-- И тут че не делай, все одна фигня. План вроде хороший.
+
+-- Витрина - lesson_popularity_ranking
+-- Тут тоже ничего не вышло - я начниаю чувствовать себя тупым от того что не могу улучшить нигде время запроса.
+
+-- Витрина - conversion_funnel
+-- Здесь тоже ничего не вышло - со стороны план запроса выглядит хорошо. Ускорить время запроса не вышло.