pet gp postgre done

2025-12-09 20:02:19 +03:00
parent 53398bc3ad
commit 2f80be77ed
2 changed files with 323 additions and 0 deletions
@@ -0,0 +1,143 @@
+create table users(
+	id int primary key,
+	name varchar(255),
+	age int,
+	email varchar(255),
+	registration_date date 
+);
+
+insert into 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');
+
+create table courses(
+	id int primary key,
+	title varchar(255),
+	category varchar(255),
+	created_at date 
+);
+
+insert into 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');
+
+create table lessons(
+	id int primary key,
+	course_id int,
+	title varchar(255),
+	duration_min int,
+	foreign key (course_id) references courses(id)
+);
+	
+insert into 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);
+
+create table enrollments(
+	id int primary key,
+	user_id int,
+	course_id int,
+	enrolled_at date,
+	foreign key (user_id) references users(id),
+	foreign key (course_id) references courses(id)
+);
+
+insert into 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');
+
+create table lesson_views(
+	id int primary key,
+	user_id int,
+	lesson_id int,
+	viewed_at timestamp,
+	foreign key (user_id) references users(id),
+	foreign key (lesson_id) references lessons(id)
+);
+
+insert into 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');
+
+
+create materialized view user_activity_summary as (
+with available_lessons as (
+	select 
+		e.user_id,
+		count(distinct l.id) as cnt_lesson
+	from lessons l
+	join enrollments e on e.course_id = l.course_id 
+	group by e.user_id
+)
+select 
+	u.id,
+	u.name,
+	count(distinct e.course_id) as enrrollment_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 lv.lesson_id) * 100.0 / al.cnt_lesson
+	,2) || '%' as engagegement_rate
+from users u
+join enrollments e on u.id = e.user_id 
+join lesson_views lv on lv.user_id = u.id 
+join available_lessons al on al.user_id = u.id 
+group by u.id, u.name, al.cnt_lesson
+);
+
+create materialized view course_summary as(
+with view_cnt as (
+	select l.course_id,
+	count(lv.lesson_id) cnt
+	from lessons l
+	join lesson_views lv on l.id = lv.lesson_id
+	group by l.course_id	
+)
+select 
+    c.id as course_id,
+	c.title,
+	count(distinct e.user_id) unique_users,
+	count(distinct l.id) lessons_count,
+	vc.cnt total_views,
+	round(vc.cnt * 1.0 / count(distinct e.user_id), 2) as avg_views_per_user,
+	min(lv.viewed_at) as first_viewed_at,
+	max(lv.viewed_at) as last_viewed_at
+from
+	courses c
+	join lessons l on c.id = l.course_id
+	join enrollments e on e.course_id = c.id 
+	join view_cnt vc on vc.course_id = c.id 
+	join lesson_views lv on lv.lesson_id = l.id
+group by c.title, vc.cnt, c.id 
+order by course_id
+);
+
+create materialized view platform_summary as (
+select 
+	count(distinct u.id) as total_users,
+	count(distinct c.id) as total_courses,
+	count(distinct l.id) as total_lessons,
+	count(distinct lv.user_id) as users_with_views,
+	round(count(distinct l.id) * 1.0 / count(distinct c.id), 2) as avg_lessons_per_course,
+	count(lv.lesson_id) * 1.0 / count(distinct l.id)  as avg_lessons_per_lesson
+from users u
+left join lesson_views lv on lv.user_id = u.id
+left join lessons l on l.id = lv.lesson_id
+left join courses c on c.id = l.course_id
+);
+