Собрал всё в 1 папку

2025-12-07 17:01:30 +04:00
parent cd513f80f7
commit 94c13a3a74
21 changed files with 0 additions and 0 deletions
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+DROP SCHEMA IF EXISTS edu_platform CASCADE;
+CREATE SCHEMA edu_platform;
+
+drop table if exists edu_platform.users;
+CREATE TABLE edu_platform.users (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(100) NOT NULL,
+    age INT NOT NULL,
+    email VARCHAR(100) NOT NULL, 
+    registration_date DATE NOT NULL
+);
+
+drop table if exists edu_platform.courses;
+CREATE TABLE edu_platform.courses (
+	id SERIAL PRIMARY KEY,
+	title VARCHAR(100) NOT NULL,
+	category VARCHAR(100) NOT NULL,
+    created_at DATE not NULL
+);
+
+drop table if exists edu_platform.lessons;
+create TABLE edu_platform.lessons (
+	id SERIAL PRIMARY KEY,
+	course_id INT NOT NULL,
+	title VARCHAR(100) NOT NULL,
+	duration_min INT NOT null,
+	FOREIGN KEY (course_id) REFERENCES edu_platform.courses(id)
+);
+
+drop table if exists edu_platform.enrollments;
+create TABLE edu_platform.enrollments (
+	id SERIAL PRIMARY KEY,
+	user_id	INT NOT NULL,
+	course_id INT NOT NULL,
+	enrolled_at DATE not null,
+	foreign key (user_id) references edu_platform.users(id),
+	foreign key (course_id) references edu_platform.courses(id)
+);
+
+drop table if exists edu_platform.lesson_views;
+create table edu_platform.lesson_views (
+	id SERIAL PRIMARY KEY,
+	user_id	INT NOT NULL,
+	lesson_id INT NOT NULL,
+	viewed_at TIMESTAMP not null,
+	foreign key (user_id) references edu_platform.users(id),
+	foreign key (lesson_id) references edu_platform.lessons(id)
+);
+
+
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+INSERT INTO edu_platform.users (id, name, age, email, registration_date) VALUES 
+(1, 'Alice', 25, 'alice@mail.com', '2023-01-10'),
+(2,'Bob', 30, 'bob@gmail.com', '2023-02-05'),
+(3,'Charlie', 22, 'charlie@mail.com', '2023-02-20'),
+(4,'Diana', 28, 'diana@mail.com', '2023-03-01'),
+(5,'Ethan', 35, 'ethan@gmail.com', '2023-03-10');
+    
+    
+
+INSERT INTO edu_platform.courses (id, title, category, created_at) VALUES
+(1, 'SQL для начинающих', 'data', '2023-01-01'),
+(2, 'Python для анализа данных', 'programming', '2023-01-15'),
+(3, 'BI с нуля', 'business', '2023-03-01');
+
+-- Таблица lessons
+INSERT INTO edu_platform.lessons (id, course_id, title, duration_min) VALUES
+(1, 1, 'SELECT и FROM', 10),
+(2, 1, 'JOIN', 15),
+(3, 2, 'Pandas', 20),
+(4, 3, 'Основы BI', 12),
+(5, 3, 'Метрики и дашборды', 18);
+
+-- Таблица enrollments
+INSERT INTO edu_platform.enrollments (id, user_id, course_id, enrolled_at) VALUES
+(1, 1, 1, '2023-01-15'),
+(2, 1, 2, '2023-02-01'),
+(3, 2, 1, '2023-01-20'),
+(4, 3, 2, '2023-03-05'),
+(5, 4, 3, '2023-04-01');
+
+-- Таблица lesson_views
+INSERT INTO edu_platform.lesson_views (id, user_id, lesson_id, viewed_at) VALUES
+(1, 1, 1, '2023-01-16 10:00:00'),
+(2, 1, 2, '2023-01-16 10:15:00'),
+(3, 2, 1, '2023-01-21 09:00:00'),
+(4, 3, 3, '2023-03-06 12:00:00'),
+(5, 4, 4, '2023-04-02 10:00:00'),
+(6, 4, 5, '2023-04-03 10:00:00');
@@ -0,0 +1,74 @@
+-- Активность пользователей
+
+-- До анализа EXPLAIN:
+drop  Materialized VIEW if exists edu_platform.user_activity_summary;
+create Materialized VIEW edu_platform.user_activity_summary as 
+select
+	u.id as user_id ,
+	u.name as name,
+	COUNT(distinct e.course_id) as enrollment_count,
+	COUNT(distinct lv.lesson_id) as viewed_lessons_count,
+	MAX(lv.viewed_at) as last_view,
+	MIN(lv.viewed_at) as first_view,
+	ROUND(
+		COUNT(DISTINCT l.id) * 100.0 / NULLIF(COUNT(distinct l2.id), 0), 
+		2) as engagement_rate
+from
+	edu_platform.users u 
+left join edu_platform.enrollments e on u.id = e.user_id
+inner join edu_platform.lesson_views lv on u.id = lv.user_id
+left join edu_platform.lessons l on lv.lesson_id  = l.id
+left join edu_platform.lessons l2 on e.course_id  = l2.course_id
+group by 
+	u.id, u.name;
+
+-- После анализа EXPLAIN
+-- Убрал диблирование строк, возникающее при Join-ах.
+-- Минимизировал DISTINCT.
+
+
+drop  Materialized VIEW if exists edu_platform.user_activity_summary;
+create Materialized VIEW edu_platform.user_activity_summary as 
+WITH 
+course_lessons AS (
+    SELECT course_id, COUNT(*) AS lesson_count
+    FROM edu_platform.lessons
+    GROUP BY course_id
+),
+users_enroll as (
+	select
+		u.id as user_id ,
+		u.name as name,
+		COUNT(DISTINCT e.course_id) as enrollment_count,
+		SUM(cl.lesson_count) as lesson_sum
+	from
+		edu_platform.users u
+	left join edu_platform.enrollments e on u.id = e.user_id
+	left join course_lessons cl on e.course_id = cl.course_id
+	group by u.id, u.name
+),
+users_lesson_views as (
+	select
+		lv.user_id,
+		COUNT(distinct lv.lesson_id) as viewed_lessons_count,
+		MAX(lv.viewed_at) as last_view,
+		MIN(lv.viewed_at) as first_view
+	from
+		edu_platform.lesson_views lv
+	group by lv.user_id
+)
+select 
+	ue.user_id,
+	ue.name,
+	ue.enrollment_count,
+	ulv.viewed_lessons_count,
+	ulv.last_view,
+	ulv.first_view,
+	ROUND( (nullif(ulv.viewed_lessons_count, 0) * 100.0) / ue.lesson_sum,
+	2) as engagement_rate
+from users_enroll ue
+left join users_lesson_views ulv on ue.user_id = ulv.user_id;
+
+
+
+
@@ -0,0 +1,51 @@
+-- Эффективность курсов
+
+-- После анализа EXPLAIN
+-- Убрал диблирование строк, возникающее при Join-ах.
+-- Минимизировал DISTINCT.
+drop  Materialized VIEW if exists edu_platform.course_summary;
+create Materialized VIEW edu_platform.course_summary as 
+with
+enroll as (
+	select 
+		course_id, 
+		COUNT(DISTINCT user_id) as unique_users -- Может ли один и тот же юзер записаться на курс больше одного раза? Если да, то нужен DISTINCT
+	from 
+		edu_platform.enrollments 
+	group by 
+		course_id),
+lessons as (
+	select 
+		course_id,
+		COUNT(*) as lessons_count
+	from 
+		edu_platform.lessons
+	group by 
+		course_id),
+views as (
+	select 
+		l.course_id as course_id,
+		count(*) as total_views,
+		MIN(lv.viewed_at) as first_view,
+		MAX(lv.viewed_at) as last_view
+	from 
+		edu_platform.lesson_views lv
+	left join edu_platform.lessons l on lv.lesson_id = l.id
+	group by 
+		l.course_id)
+select
+    c.id AS course_id,
+    c.title AS course_title,
+	e.unique_users,
+	l.lessons_count,
+	v.total_views,
+	ROUND( v.total_views * 1.0 / nullif(e.unique_users, 0)
+		,2
+		) as avg_views_per_user,
+	v.first_view,
+	v.last_view
+from
+	edu_platform.courses c
+LEFT JOIN enroll e ON c.id = e.course_id
+LEFT JOIN lessons l ON c.id = l.course_id
+LEFT JOIN views v ON c.id = v.course_id;
@@ -0,0 +1,21 @@
+-- Общая отчетность по взаимодействию
+
+drop  Materialized VIEW if exists edu_platform.platform_summary;
+create Materialized VIEW edu_platform.platform_summary as 
+select
+	(select COUNT(*) from edu_platform.users) as total_users,
+	(select COUNT(*) from edu_platform.courses) as total_courses,
+	(select COUNT(*) from edu_platform.lessons) as total_lessons,
+	(select COUNT(distinct user_id) from edu_platform.lesson_views) as users_with_views,
+	ROUND(
+		(select AVG(t1.cnt) from 
+			(select course_id, COUNT(id) cnt 
+			from edu_platform.lessons 
+			group by course_id) t1) 
+		,2) as avg_lessons_per_course,
+	ROUND(
+		(select AVG(t2.cnt) from
+			(select lesson_id, COUNT(id) cnt 
+			from edu_platform.lesson_views 
+			group by lesson_id) t2)	
+		,2) as avg_views_per_lesson;