Merge branch 'main' into ebelykh

amaksatov/postgresql/OS-329.sql

@@ -0,0 +1,215 @@
+CREATE TABLE IF NOT EXISTS amaksatov.users (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(100),
+    age INT,
+    email VARCHAR(255),
+    registration_date DATE
+);
+
+CREATE TABLE IF NOT EXISTS amaksatov.courses (
+    id SERIAL PRIMARY KEY,
+    title VARCHAR(255),
+    category VARCHAR(100),
+    created_at DATE
+);
+
+CREATE TABLE IF NOT EXISTS amaksatov.lessons (
+    id SERIAL PRIMARY KEY,
+    course_id INT,
+    title VARCHAR(255),
+    duration_min INT,
+    FOREIGN KEY (course_id) REFERENCES amaksatov.courses(id)
+);
+
+CREATE TABLE IF NOT EXISTS amaksatov.enrollments (
+    id SERIAL PRIMARY KEY,
+    user_id INT,
+    course_id INT,
+    enrolled_at date,
+    FOREIGN KEY (user_id) REFERENCES amaksatov.users(id),
+    FOREIGN KEY (course_id) REFERENCES amaksatov.courses(id)
+);
+
+CREATE TABLE IF NOT EXISTS amaksatov.lesson_views (
+    id SERIAL PRIMARY KEY,
+    user_id INT,
+    lesson_id INT,
+    viewed_at TIMESTAMP,
+    FOREIGN KEY (user_id) REFERENCES amaksatov.users(id),
+    FOREIGN KEY (lesson_id) REFERENCES amaksatov.lessons(id)
+);
+
+
+INSERT
+    INTO
+    amaksatov.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'
+);
+
+SELECT * FROM amaksatov.users;
+
+
+INSERT
+    INTO
+    amaksatov.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'
+);
+
+INSERT
+    INTO
+    amaksatov.lessons (
+        course_id,
+        title,
+        duration_min
+    )
+VALUES
+(
+    1,
+    'SELECT и FROM',
+    10
+),
+(
+    1,
+    'JOIN',
+    15
+),
+(
+    2,
+    'Pandas',
+    20
+),
+(
+    3,
+    'Основы BI',
+    12
+),
+(
+    3,
+    'Метрики и дашборды',
+    18
+);
+
+INSERT
+    INTO
+    amaksatov.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'
+);
+
+INSERT
+    INTO
+    amaksatov.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'
+),
+(
+    2,
+    1,
+    '2023-01-21 09:00:00'
+),
+(
+    3,
+    3,
+    '2023-03-06 12:00:00'
+),
+(
+    4,
+    4,
+    '2023-04-02 10:00:00'
+),
+(
+    4,
+    5,
+    '2023-04-03 10:00:00'
+);
+

amaksatov/postgresql/OS-330.sql

@@ -0,0 +1,68 @@
+
+CREATE MATERIALIZED VIEW user_activity_summary AS
+SELECT
+    u.id AS user_id, -- user_id
+    u.name, -- name
+    COUNT(DISTINCT e.course_id) AS enrollment_count, -- кол-во записей на курсы
+    COUNT(DISTINCT lv.lesson_id) AS viewed_lessons_count, -- кол-во просмотренных уроков
+    MAX(lv.viewed_at) AS last_viewed, -- последний просмотр
+    MIN(lv.viewed_at) AS first_viewed, -- первый просмотр
+    ROUND(COUNT(DISTINCT l.course_id) * 100.0 / COUNT(DISTINCT l.id), 2) || '%' AS engagement_rate -- вовлеченность(процент просмотренных/записанным)
+FROM amaksatov.users u -- основная таблица
+JOIN enrollments e ON e.user_id = u.id -- связь users с enrollments
+LEFT JOIN lesson_views lv ON lv.user_id = e.user_id -- связь lessons с lesson_views
+JOIN lessons l ON l.course_id = e.course_id  -- связь уроков с курсами пользователя
+GROUP BY u.id, u.name -- группировка по user_id и name
+ORDER BY user_id; -- сортировка по user_id
+
+
+CREATE MATERIALIZED VIEW course_summary AS
+SELECT
+    c.id AS course_id,
+    c.title AS course_title,
+    COUNT(DISTINCT e.user_id) AS unique_users,
+    COUNT(DISTINCT l.id) AS lessons_count,
+    COUNT(DISTINCT lv.id) AS total_views,
+    ROUND(
+        CASE
+            WHEN COUNT(DISTINCT e.user_id) = 0 THEN NULL
+            ELSE COUNT(DISTINCT lv.id) * 1.0 / COUNT(DISTINCT e.user_id)
+        END, 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
+LEFT JOIN enrollments e ON e.course_id = c.id
+LEFT JOIN lessons l ON c.id = l.course_id
+LEFT JOIN lesson_views lv ON lv.lesson_id = l.id
+GROUP BY c.id;
+
+
+
+
+
+CREATE MATERIALIZED VIEW platform_summary AS
+WITH
+user_stats AS (
+    SELECT COUNT(*) AS total_users FROM users
+),
+course_stats AS (
+    SELECT COUNT(*) AS total_courses FROM courses
+),
+lesson_stats AS (
+    SELECT COUNT(*) AS total_lessons FROM lessons
+),
+view_stats AS (
+    SELECT COUNT(*) AS total_views, COUNT(DISTINCT user_id) AS users_with_views
+    FROM lesson_views
+)
+
+SELECT
+    u.total_users,
+    c.total_courses,
+    l.total_lessons,
+    v.users_with_views,
+
+    ROUND(l.total_lessons::decimal / NULLIF(c.total_courses, 0), 2) AS avg_lessons_per_course,
+    ROUND(v.total_views::decimal / NULLIF(l.total_lessons, 0), 2) AS avg_views_per_lesson
+
+FROM user_stats u, course_stats c, lesson_stats l, view_stats v;

avysokih/postgresql/command order/command_order.sql

@@ -0,0 +1,53 @@
+/*Задача 1: Какой будет порядок выполнения у запросов?
+
+SELECT name, age
+FROM users
+WHERE is_active = true AND country = 'Canada'
+ORDER BY age
+LIMIT 3;
+
+*/
+
+1. FROM users
+2. WHERE is_active = true AND country = 'Canada'
+3. SELECT name, age
+4. ORDER BY age
+5. LIMIT 3
+
+ /*
+SELECT country, COUNT(*) AS active_users
+FROM users
+WHERE is_active = true
+GROUP BY country
+HAVING COUNT(*) > 1;
+ */
+
+ 1. FROM users
+ 2. WHERE is_active = true
+ 3. GROUP BY country
+ 4. HAVING COUNT(*) > 1
+ 5. SELECT country, COUNT(*) AS active_users
+
+ /*
+SELECT country, AVG(age) AS avg_age
+FROM users
+GROUP BY country
+HAVING COUNT(*) >= 3 AND AVG(age) > 25;
+ */
+
+ 1. FROM users
+ 2. GROUP BY country
+ 3. HAVING COUNT(*) >= 3 AND AVG(age) > 25
+ 4. SELECT country, AVG(age) AS avg_age
+
+ /*
+SELECT name, age
+FROM users
+WHERE is_active = false AND age > 30
+ORDER BY name;
+ */
+  
+  1. FROM users
+  2. WHERE is_active = false AND age > 30
+  3. SELECT name, age
+  4. ORDER BY name

avysokih/postgresql/filtration tasks/filtr_code.sql

@@ -0,0 +1,104 @@
+-- Создание и заполнение таблицы
+
+create table products_extended(
+id INT primary key,
+name TEXT,
+category TEXT,
+price DECIMAL,
+in_stock BOOLEAN,
+email_support TEXT
+);
+
+INSERT INTO products_extended (id, name, category, price, in_stock, email_support) VALUES
+(1, 'iPhone 14', 'smartphone', 799, TRUE, 'iphone@apple.com'),
+(2, 'MacBook Air', 'laptop', 1199, FALSE, NULL),
+(3, 'Galaxy S22', 'smartphone', 699, TRUE, 'galaxy@support.com'),
+(4, 'ThinkPad X1', 'laptop', 1399, TRUE, 'thinkpad@lenovo.com'),
+(5, 'iPad Pro', 'tablet', 999, FALSE, 'ipad@apple.com'),
+(6, 'Kindle Paperwhite', 'ebook_reader', 149, TRUE, NULL),
+(7, 'Mi Band 7', 'smartwatch', 49, TRUE, 'miband@xiaomi.com'),
+(8, 'Surface Pro', 'tablet', 1299, TRUE, 'surface@microsoft.com'),
+(9, 'Honor Pad X9', 'tablet', 219, TRUE, 'honor@support.com'),
+(10, 'Dell XPS 13', 'laptop', 1099, FALSE, 'dell@support.com');
+
+/*
+Задача 1:
+Выведи все товары, которые:
+- в наличии
+- НЕ относятся к `smartwatch` и `ebook_reader`
+- стоят от 300 до 1300
+И для них посчитай:
+1. price с наценкой 10%
+2. price с НДС 20%
+3. Статус: если email_support IS NULL, подставь нет почты, иначе — сам email
+*/
+
+
+select name, category, price, price * 1.1 as price_with_markup, price * 1.2 as price_with_vat, coalesce(email_support, 'нет почты') as status
+from  products_extended 
+where in_stock = true and category not in ('smartwatch', 'ebookreader') and price between 300 and 1300;
+
+/*
+Задача 2:
+Найти все товары:
+1. У которых цена меньше 150 или больше 1200
+2. У которых** есть email поддержки
+Для каждого выведи:
+1. Название
+2. Категорию
+3. Email
+4. Цену с прибавкой 25%
+5. Отметку `premium` — если цена > 1000
+*/
+
+select name, category, email_support, price * 1.25 as price_25, (price> 1000) as premium
+from products_extended
+where (price < 150 or price > 1200) and email_support is not null
+order by premium;
+
+/*
+Задача 3:
+Найди все товары:
+- где категория — `smartphone`, `laptop`, `tablet`
+- название НЕ содержит `'i'` (чтобы исключить Apple)
+- цена от 500 до 1300
+Выведи:
+- `id`, `name`, `category`, `price`
+- отсортируй по `id`
+*/
+
+select id, name, category, price 
+from products_extended
+where category in('smartphone', 'laptop', 'tablet') and name not like '%i%' and price between 500 and 1300
+order by id desc;
+
+/*
+Задача 4:
+Найди товары, у которых:
+- email_support IS NULL
+- они в наличии
+- стоят менее 800
+Выведи:
+- `name`, `category`, `price`
+- добавь колонку `comment`: `'нет поддержки'`
+*/
+
+select name, category, price, coalesce (email_support, 'нет поддержки') as comment
+from products_extended
+where email_support is null and in_stock is not null and price < 800;
+
+/*
+Задача 5:
+Найди товары, у которых:
+- название заканчивается на `'Pro'` ИЛИ содержит `'X'` внутри (например, `X1`, `XPS`)
+- в наличии
+- с ценой > 700
+Выведи:
+- `name`, `category`, `price`
+- флаг `premium` — `true`, если `price > 1000`, иначе `false`
+*/
+
+select name, category, price, (price>1000) as premium
+from products_extended
+where (name like '%Pro%' or name like '%X%') and in_stock is true and price > 700
+order by price desc;

avysokih/postgresql/test_db.sql

@@ -0,0 +1 @@
+CREATE TABLE test_db;#

avysokih/postgresql/window functions/win_func_tasks.sql

@@ -0,0 +1,86 @@
+/*
+Задача 1:
+
+Для каждой категории показать 2 строки:
+- Самый дорогой товар с email'ом
+- Самый дорогой товар без email'а
+*/
+with with_mail as (
+select category, name, price, email_support
+from (
+select category, name, price, email_support,
+row_number() over (partition by category order by price desc) as rn
+from products_extended 
+where email_support is not null
+) t
+where rn = 1
+),
+without_mail as (
+select category, name, price, email_support
+from (
+select category, name, price, email_support,
+row_number() over (partition by category order by price desc) as rn
+from products_extended
+where email_support is null
+) t
+where rn = 1 
+)
+
+select * from with_mail
+union all
+select * from without_mail
+order by category;
+
+/*
+Задача 2:
+
+Для каждого товара показать:
+
+- `name` — название товара
+- `category` — категория товара
+- `price` — цена текущего товара
+- `next_price` — цена следующего товара внутри той же категории, упорядоченного по цене
+- `diff` — разница между ценой текущего товара и ценой следующего товара 
+(`price - next_price`)
+*/
+
+with t as(
+select name, category, price,
+lead(price) over (partition by category order by price) as next_price
+from products_extended)
+select name, category, price, next_price,
+price - next_price as diff
+from t order by category;
+
+/*
+Задача 3:
+
+Показать `category`, `name`, `price`, `cumulative_sales`
+
+Где `cumulative_sales` — это сумма `price` **внутри категории** по мере возрастания цены
+*/
+
+select category, name, price, 
+sum(price) over (partition by category order by price) as cumulative_sales
+from products_extended;
+
+/*
+Задача 4:
+
+Вывести `category`, `name`, `price`, `avg_price`, `is_above_avg`
+
+Где `avg_price` — средняя цена по категории
+
+`is_above_avg = true`, если `price > avg_price`
+
+*/
+
+
+with t as(
+select category, name, price,
+round(avg(price) over (partition by category), 1) as avg_price
+from products_extended)
+select category, name, price, avg_price,
+price > avg_price as is_above_avg
+from t order by category;
+

bhabibullin/clickhouse/clickhouse_pet.sql

@@ -0,0 +1,415 @@
+--ПЕТ ПРОЕКТ СОЗДАНИЕ ТАБЛИЦ
+
+CREATE TABLE bhabibullin.core_enrollments
+ON CLUSTER clickhouse_cluster
+(
+	user_id 	UInt32,
+	course_id 	UInt32,
+	enrolled_at	DateTime
+)
+ENGINE = ReplicatedMergeTree(
+	'/clickhouse/tables/{shard}/bhabibullin/core_enrollments',
+	'{replica}'
+)
+ORDER BY (user_id, enrolled_at);
+
+
+CREATE TABLE bhabibullin.core_dim_user
+ON CLUSTER clickhouse_cluster
+(
+	user_id 	 	  UInt32,
+	name 			  String,
+	age			   	  UInt32,
+	email 			  String,
+	registration_date Date
+)
+ENGINE = ReplicatedMergeTree(
+	'/clickhouse/tables/{shard}/bhabibullin/core_dim_user',
+	'{replica}'
+)
+ORDER BY (user_id, registration_date);
+
+
+CREATE TABLE bhabibullin.core_fact_lesson_views
+ON CLUSTER clickhouse_cluster
+(
+    user_id   UInt32, 
+    lesson_id UInt32,
+    course_id UInt32,
+    viewed_at DateTime64(3)
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/bhabibullin/core_fact_lesson_views',
+    '{replica}'
+)
+ORDER BY user_id;
+
+CREATE TABLE bhabibullin.core_dim_course
+ON CLUSTER clickhouse_cluster
+(
+	course_id	UInt32,
+	title	 	String,
+	category	String
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/bhabibullin/core_dim_course',
+    '{replica}'
+)
+ORDER BY course_id;
+
+drop table bhabibullin.core_dim_course ;
+
+CREATE TABLE bhabibullin.core_dim_lesson
+ON CLUSTER clickhouse_cluster
+(
+	lesson_id		UInt32,
+	title			String,
+	duration_min	UInt32,
+	course_id		UInt32
+)
+ENGINE = ReplicatedMergeTree(
+	'/clickhouse/tables/{shard}/bhabibullin/core_dim_lesson',
+	'{replica}'
+)
+ORDER BY (lesson_id, course_id);
+
+
+-- Этап 2. Создание витринных таблиц
+-- Задание 2: Подготовь структуру витрины lesson_popularity_summary
+/*
+- Спроектируй таблицу, где каждая строка — один урок.
+- Для каждого урока должны храниться:
+    - ID и название урока
+    - ID и название курса, к которому он относится
+    - Общее число просмотров
+    - Количество уникальных пользователей, посмотревших урок
+    - Дата первого и последнего просмотра
+ */
+
+-- Основная таблица с AggregatingMergeTree
+
+CREATE TABLE bhabibullin.lesson_popularity_summary
+ON CLUSTER clickhouse_cluster
+(
+    lesson_id     UInt32,
+    lesson_title  String,
+    course_id     UInt32,
+    course_title  String,
+    total_views   AggregateFunction(sum, UInt64),
+    unique_users  AggregateFunction(uniq, UInt32),
+    first_view    AggregateFunction(min, DateTime64(3, 'UTC')),
+    last_view     AggregateFunction(max, DateTime64(3, 'UTC'))
+)
+ENGINE = ReplicatedAggregatingMergeTree(
+    '/clickhouse/tables/{shard}/bhabibullin/lesson_popularity_summary',
+    '{replica}'
+)
+ORDER BY (lesson_id, course_id)
+SETTINGS index_granularity = 8192;
+
+CREATE MATERIALIZED VIEW bhabibullin.mv_lesson_popularity_summary
+ON CLUSTER clickhouse_cluster
+TO bhabibullin.lesson_popularity_summary
+AS
+SELECT
+    flv.lesson_id AS lesson_id,
+    l.title AS lesson_title,
+    flv.course_id AS course_id,
+    c.title AS course_title,
+    sumState(1) AS total_views,
+    uniqState(flv.user_id) AS unique_users,
+    minState(flv.viewed_at) AS first_view,
+    maxState(flv.viewed_at) AS last_view
+FROM core_fact_lesson_views AS flv
+JOIN core_dim_lesson AS l ON flv.lesson_id = l.lesson_id
+JOIN core_dim_course AS c ON flv.course_id = c.course_id
+GROUP BY
+    flv.lesson_id,
+    l.title,
+    flv.course_id,
+    c.title;
+
+INSERT INTO bhabibullin.lesson_popularity_summary
+SELECT
+    flv.lesson_id,
+    l.title AS lesson_title,
+    flv.course_id,
+    c.title AS course_title,
+    count() AS total_views,
+    uniqExact(flv.user_id) AS unique_users,
+    min(flv.viewed_at) AS first_view,
+    max(flv.viewed_at) AS last_view
+FROM core_fact_lesson_views AS flv
+JOIN core_dim_lesson  AS l ON flv.lesson_id = l.lesson_id
+JOIN core_dim_course  AS c ON flv.course_id = c.course_id
+GROUP BY
+    flv.lesson_id,
+    l.title,
+    flv.course_id,
+    c.title;
+
+select * from bhabibullin.mv_lesson_popularity_summary ;
+select * from bhabibullin.lesson_popularity_summary ;
+show tables;
+
+/*
+ ### ✅ **Задание 3: Создай витрину `inactive_users_summary`**
+
+**Цель:** выявить пользователей, которые **зарегистрировались, но ничего не посмотрели**.
+
+📌 **Что нужно сделать:**
+
+- Подготовь таблицу, где каждая строка — один такой "неактивный" пользователь.
+- Для каждого пользователя нужны:
+    - ID, имя, email, возраст
+    - Количество курсов, на которые он записался
+    - Дата регистрации
+
+**Где пригодится:**
+
+Эта витрина может использоваться для продуктовой аналитики, триггерных рассылок (например, напоминаний), анализа оттока, повышения вовлечённости.
+ */ 
+
+DROP TABLE bhabibullin.inactive_users_summary;
+DROP VIEW bhabibullin.mv_inactive_users_summary ;
+show tables;
+
+CREATE TABLE bhabibullin.inactive_users_summary
+ON CLUSTER clickhouse_cluster
+(
+	user_id  		  UInt32,
+	name		      String,
+	email 		      String,
+	age 		      UInt32,
+	enrollment_count  UInt32,
+	registration_date Date
+)
+ENGINE = ReplicatedMergeTree(
+	'/clickhouse/tables/{shard}/bhabibullin/inactive_users_summary',
+	'{replica}'
+)
+ORDER BY user_id;
+
+CREATE MATERIALIZED VIEW bhabibullin.mv_inactive_users_summary 
+ON CLUSTER clickhouse_cluster
+TO bhabibullin.inactive_users_summary 
+AS
+SELECT  
+    cdu.user_id,
+    cdu.name,
+    cdu.email,
+    cdu.age,
+    countDistinct(flv.course_id) as enrollment_count,
+    cdu.registration_date
+FROM core_dim_user cdu 
+LEFT ANTI JOIN core_fact_lesson_views flv 
+    ON cdu.user_id = flv.user_id
+GROUP BY 
+    cdu.user_id,
+    cdu.name,
+    cdu.email,
+    cdu.age,
+    cdu.registration_date;
+
+INSERT INTO bhabibullin.inactive_users_summary
+SELECT  
+	cdu.user_id,
+    cdu.name,
+    cdu.email,
+    cdu.age,
+    0 as enrollment_count,
+    cdu.registration_date
+FROM core_dim_user cdu 
+WHERE (cdu.user_id, 1) NOT IN (
+    SELECT user_id, 1 
+    FROM core_enrollments
+    GROUP BY user_id
+);
+
+select * from bhabibullin.inactive_users_summary ius ;
+select * from bhabibullin.mv_inactive_users_summary mius ;
+
+/*
+ ### ✅ **Задание 4: Создай витрину `course_completion_rate`**
+
+**Цель:** проанализировать, насколько хорошо пользователи проходят курсы.
+
+📌 **Что нужно сделать:**
+
+- Сформируй таблицу, где строка — это пользователь + курс.
+- Для каждой пары нужно рассчитать:
+    - Общее число уроков в курсе
+    - Сколько из них просмотрел конкретный пользователь
+    - Коэффициент завершения (`lessons_viewed / lessons_in_course`)
+ */
+
+CREATE TABLE IF NOT EXISTS bhabibullin.course_completion_rate
+ON CLUSTER clickhouse_cluster
+(
+    user_id         UInt32,
+    user_name       String,
+    course_id       UInt32,
+    course_title    String,
+    lessons_in_course UInt32,
+    lessons_viewed  UInt32,
+    completion_rate Float64
+)
+ENGINE = ReplicatedMergeTree(
+	'/clickhouse/tables/{shard}/bhabibullin/course_completion_rate',
+	'{replica}'
+)
+ORDER BY (user_id, course_id);
+
+
+CREATE MATERIALIZED VIEW IF NOT EXISTS bhabibullin.mv_course_completion_rate
+ON CLUSTER clickhouse_cluster
+TO bhabibullin.course_completion_rate
+AS
+WITH lessons_in_course AS (
+    SELECT
+        course_id,
+        count(Distinct lesson_id) AS lessons_in_course
+    FROM core_dim_lesson
+    GROUP BY course_id
+),
+views_user_course AS (
+    SELECT
+        user_id,
+        course_id,
+        count(Distinct lesson_id) AS lessons_viewed
+    FROM core_fact_lesson_views
+    GROUP BY user_id, course_id
+)
+SELECT
+    u.user_id AS user_id, 
+    u.name AS user_name,
+    c.course_id AS course_id,
+    c.title AS course_title,
+    lic.lessons_in_course AS lessons_in_course,
+    coalesce(vuc.lessons_viewed, 0) AS lessons_viewed,
+    ROUND(
+        COALESCE(
+            NULLIF(coalesce(vuc.lessons_viewed, 0) * 1.0, 0)
+            / NULLIF(lic.lessons_in_course * 1.0, 0),
+            0
+        ),
+        2
+    ) AS completion_rate
+FROM core_dim_user u
+JOIN core_enrollments e ON u.user_id  = e.user_id
+JOIN core_dim_course c ON e.course_id = c.course_id
+JOIN lessons_in_course AS lic ON c.course_id = lic.course_id
+LEFT JOIN views_user_course AS vuc ON vuc.user_id   = u.user_id AND vuc.course_id = c.course_id
+ORDER BY
+    u.user_id,
+    c.course_id;
+
+INSERT INTO bhabibullin.course_completion_rate 
+WITH lessons_in_course AS (
+    SELECT
+        course_id,
+        count(Distinct lesson_id) AS lessons_in_course
+    FROM core_dim_lesson
+    GROUP BY course_id
+),
+views_user_course AS (
+    SELECT
+        user_id,
+        course_id,
+        count(Distinct lesson_id) AS lessons_viewed
+    FROM core_fact_lesson_views
+    GROUP BY user_id, course_id
+)
+SELECT
+    u.user_id AS user_id, 
+    u.name AS user_name,
+    c.course_id AS course_id,
+    c.title AS course_title,
+    lic.lessons_in_course AS lessons_in_course,
+    coalesce(vuc.lessons_viewed, 0) AS lessons_viewed,
+    ROUND(
+        COALESCE(
+            NULLIF(coalesce(vuc.lessons_viewed, 0) * 1.0, 0)
+            / NULLIF(lic.lessons_in_course * 1.0, 0),
+            0
+        ),
+        2
+    ) AS completion_rate
+FROM core_dim_user u
+JOIN core_enrollments e ON u.user_id  = e.user_id
+JOIN core_dim_course c ON e.course_id = c.course_id
+JOIN lessons_in_course AS lic ON c.course_id = lic.course_id
+LEFT JOIN views_user_course AS vuc ON vuc.user_id   = u.user_id AND vuc.course_id = c.course_id;
+
+select * from bhabibullin.course_completion_rate;
+select * from bhabibullin.mv_course_completion_rate;
+
+/*
+ # 📊 Этап 3. Анализ и запросы
+
+### ✅ **Задание 5: Напиши SQL-запросы к витринам**
+
+**Напиши свои вариации для практики.**
+ */
+
+--Топ-5 самых просматриваемых уроков
+SELECT 
+    lesson_title,
+    course_title,
+    total_views
+FROM lesson_popularity_summary
+ORDER BY total_views DESC
+LIMIT 5;
+
+--Неактивные пользователи, записавшиеся на курсы
+SELECT 
+    name,
+    email,
+    enrollment_count
+FROM inactive_users_summary
+WHERE enrollment_count > 0
+ORDER BY registration_date DESC;
+
+--Курсы с самым высоким процентом завершения
+SELECT 
+    course_title,
+    AVG(completion_rate) AS avg_completion
+FROM course_completion_rate
+GROUP BY course_title
+ORDER BY avg_completion DESC
+LIMIT 5;
+
+-- топ 5 курсов по количеству уникальных пользователей
+SELECT
+    course_title,
+    unique_users
+FROM lesson_popularity_summary
+ORDER BY unique_users DESC
+LIMIT 5;
+
+--новые пользователи за прошлый месяц 
+SELECT
+    user_id,
+    name,
+    email,
+    registration_date
+FROM core_dim_user
+WHERE registration_date >= today() - INTERVAL 30 DAY
+ORDER BY registration_date DESC;
+
+/*
+ ### ✅ **Задание 6: Сравни данные с Greenplum**
+  
+1. Выбери 2–3 значения из таблиц `_summary_source` в Greenplum
+2. Сравни с ClickHouse-результатами:
+    - Совпадает ли `SUM`, `AVG`, `MIN`, `MAX`
+    - Проверяй `NULL`, `0`, округления
+3. Напиши мини-отчёт: **"где совпадает, где нет, почему"
+
+Совпадает ли SUM, AVG, MIN, MAX
+Совпадает и в гринплам, и в кликхаус
+
+Проверяй NULL, 0, округления
+С этим даже траблы были при пет проекте, кликхаус тяжело обрабатывает нулл значения
+*/
+

bhabibullin/greenplum/pet_project_gp.sql

@@ -0,0 +1,218 @@
+CREATE SCHEMA raw;    
+CREATE SCHEMA core;     
+CREATE SCHEMA dm;
+
+CREATE TABLE raw.users (
+    id INT,
+    name VARCHAR(255),
+    age INT,
+    email VARCHAR(255),
+    registration_date DATE
+);
+
+CREATE TABLE raw.courses (
+    id INT,
+    title VARCHAR(255),
+    category VARCHAR(255),
+    created_at DATE
+);
+
+CREATE TABLE raw.lessons (
+    id INT,
+    course_id INT,
+    title VARCHAR(255),
+    duration_min INT
+);
+
+CREATE TABLE raw.enrollments (
+    id INT,
+    user_id INT,
+    course_id INT,
+    enrolled_at DATE
+);
+
+CREATE TABLE raw.lesson_views (
+    id INT,
+    user_id INT,
+    lesson_id INT,
+    viewed_at TIMESTAMP
+);
+
+CREATE TABLE core.dim_user (
+    user_id INT PRIMARY KEY,
+    name TEXT,
+    age INT,
+    email TEXT,
+    registration_date DATE
+);
+
+CREATE TABLE core.dim_course (
+    course_id INT PRIMARY KEY,
+    title TEXT,
+    category TEXT
+);
+
+CREATE TABLE core.dim_lesson (
+    lesson_id INT PRIMARY KEY,
+    title TEXT,
+    duration_min INT,
+    course_id INT REFERENCES core.dim_course(course_id)
+);
+
+CREATE TABLE core.fact_lesson_views (
+    user_id INT REFERENCES core.dim_user(user_id),
+    lesson_id INT REFERENCES core.dim_lesson(lesson_id),
+    course_id INT REFERENCES core.dim_course(course_id),
+    viewed_at TIMESTAMP
+);
+
+CREATE TABLE core.enrollments (
+    user_id INT REFERENCES core.dim_user(user_id),
+    course_id INT REFERENCES core.dim_course(course_id),
+    enrolled_at TIMESTAMP
+);
+
+INSERT INTO core.dim_user (user_id, name, age, email, registration_date)
+SELECT DISTINCT 
+    id::INT,
+    name::TEXT,
+    age::INT,
+    email::TEXT,
+    registration_date::DATE  
+FROM raw.users;
+
+INSERT INTO core.dim_course (course_id, title, category)
+SELECT DISTINCT 
+    id::INT,
+    title::TEXT,
+    category::TEXT
+FROM raw.courses;
+
+INSERT INTO core.dim_lesson (lesson_id, title, duration_min, course_id)
+SELECT DISTINCT 
+    id::INT,
+    title::TEXT,
+    duration_min::INT,
+    course_id::INT
+FROM raw.lessons;
+
+INSERT INTO core.fact_lesson_views (user_id, lesson_id, course_id, viewed_at)
+SELECT DISTINCT
+    rw.user_id::INT,
+    rw.lesson_id::INT,
+    l.course_id::INT,
+    rw.viewed_at::TIMESTAMP
+FROM raw.lesson_views rw
+JOIN raw.lessons l ON rw.lesson_id = l.id;
+
+
+INSERT INTO core.enrollments (user_id, course_id, enrolled_at)
+SELECT DISTINCT 
+    user_id::INT,
+    course_id::INT,
+    enrolled_at::DATE
+FROM raw.enrollments;
+
+CREATE MATERIALIZED VIEW dm.dm_lesson_popularity_summary AS
+SELECT 
+    dl.lesson_id,
+    dl.title AS lesson_title,
+    dc.course_id,
+    dc.title AS course_title,
+    COUNT(*) AS total_views,
+    COUNT(DISTINCT flv.user_id) AS unique_users,
+    MIN(flv.viewed_at) AS first_view,
+    MAX(flv.viewed_at) AS last_view
+FROM core.dim_lesson dl
+JOIN core.dim_course dc ON dc.course_id = dl.course_id
+JOIN core.fact_lesson_views flv ON flv.lesson_id = dl.lesson_id
+GROUP BY dl.lesson_id, dl.title, dc.course_id, dc.title;
+
+
+/*
+
+ Цель:
+    Показать популярность каждого урока.
+
+  Поля витрины:
+    - lesson_id      — идентификатор урока
+    - lesson_title   — название урока
+    - course_id      — идентификатор курса
+    - course_title   — название курса
+    - total_views    — общее число просмотров урока
+    - unique_users   — количество уникальных пользователей
+    - first_view     — дата первого просмотра
+    - last_view      — дата последнего просмотра
+
+*/
+
+
+CREATE MATERIALIZED VIEW dm.dm_inactive_users_summary AS
+SELECT 
+    du.user_id,
+    du.name AS user_name,
+    du.email,
+    du.age,
+    COUNT(DISTINCT e.course_id) AS enrollments_count,
+    du.registration_date
+FROM core.dim_user du
+LEFT JOIN core.enrollments e ON e.user_id = du.user_id
+WHERE NOT EXISTS (
+    SELECT 1 
+    FROM core.fact_lesson_views flv 
+    WHERE flv.user_id = du.user_id
+)
+GROUP BY du.user_id, du.name, du.email, du.age, du.registration_date;
+
+/*
+
+Цель:
+    Определить невовлечённых пользователей и потенциальный отток.
+
+  Поля витрины:
+    - user_id            — идентификатор пользователя
+    - user_name          — имя
+    - email              — почта
+    - age                — возраст
+    - enrollments_count  — количество курсов
+    - registration_date  — дата регистрации
+
+*/
+
+CREATE MATERIALIZED VIEW dm.course_completion_rate AS
+SELECT 
+    du.user_id,
+    du.name AS user_name,
+    c.course_id,
+    c.title AS course_title,
+    COUNT(DISTINCT dl.lesson_id) AS lessons_in_course,
+    COUNT(DISTINCT flv.lesson_id) AS lessons_viewed,
+    ROUND(
+        COUNT(DISTINCT flv.lesson_id) * 1.0 / 
+        NULLIF(COUNT(DISTINCT dl.lesson_id), 0), 
+        2
+    ) AS completion_rate
+FROM core.dim_user du
+JOIN core.enrollments e ON du.user_id = e.user_id
+JOIN core.dim_course c ON e.course_id = c.course_id
+JOIN core.dim_lesson dl ON c.course_id = dl.course_id
+LEFT JOIN core.fact_lesson_views flv ON dl.lesson_id = flv.lesson_id 
+    AND flv.user_id = du.user_id
+GROUP BY du.user_id, du.name, c.course_id, c.title
+ORDER BY du.user_id, c.course_id;
+
+/*
+
+ Цель:
+    Анализировать, насколько пользователи проходят курсы до конца.
+
+  Поля витрины:
+    - user_id            — идентификатор пользователя
+    - user_name          — имя пользователя
+    - course_id          — идентификатор курса
+    - course_title       — название курса
+    - total_lessons      — количество уроков в курсе
+    - lessons_viewed     — число просмотренных уроков
+    - completion_rate    — lessons_viewed / total_lessons
+
+*/

bhabibullin/postgre/postrge_pet_project.sql

@@ -0,0 +1,182 @@
+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 / NULLIF(al.cnt_lesson, 0), 4) as engagement_rate
+from users u
+join enrollments e on u.id = e.user_id 
+left 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
+);
+
+/*  
+	Витрина user_activity_summary
+	Цель - показать аналитику вовлеченности пользователей в обучение на платформе
+
+	user_id			     - идентификатор пользователя
+	name 			     - имя пользователя
+	enrollment_count	 - количество записей на курсы
+	viewed_lessons_count - количество просмотренных уроков
+	last_view			 - последний просмотр
+	first_view			 - первый просмотр 
+	engagement_rate 	 - вовлеченность
+
+*/
+
+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 
+	left join lesson_views lv on lv.lesson_id = l.id
+group by c.title, vc.cnt, c.id 
+order by course_id
+);
+
+/*  
+	Витрина course_summary
+	Цель - показать анализ эффективности по каждому курсу
+
+	course_id			 - идентификатор курса
+	course title 		 - название курса
+	unique_users 		 - кол-во уникальных пользователей в рамках одного курса
+	lessons_count		 - кол-во уроков
+	total_views			 - общее число просмотров уроков по курсу
+	avg_views_per_user	 - total_views / unique_users Среднее число просмотров на пользователя, записанного на курс
+	first_viewed_at		 - дата первого просмотра
+	last_viewed_at		 - дата последнего просмотра
+*/
+
+
+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 / NULLIF(count(distinct c.id), 0), 2) as avg_lessons_per_course,
+	count(lv.lesson_id) * 1.0 / NULLIF(count(distinct l.id), 0) 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
+);
+
+/*  
+	Витрина platform_summary
+	Цель - показать общую отчетность по взаимодействию
+
+	total_users  	 	   - всего пользователей
+	total_courses      	   - всего курсов
+	total_lessons          - всего уроков
+	users_with_views 	   - сколько пользователей с минимум 1 просмотром
+	avg_lessons_per_course - среднее число уроков на курс
+	avg_views_per_lesson   - среднее число просмотров на урок
+
+*/

kzhekshen/cl-house/queries/course_completion_rate.sql

@@ -51,4 +51,4 @@ FROM pet_project.fact_lesson_views flv
     GROUP BY course_id
     ) cl ON cl.course_id = l.course_id
 GROUP BY flv.user_id, l.course_id
-;
+;

mdrozdov/postgresql/create_tables.sql

@@ -0,0 +1,70 @@
+--drop table is exists users;
+create table users(
+	id int primary key,
+	name varchar(50) not null,
+	age int not null,
+	email varchar(50) not null,
+	registration_date date not null default current_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 text not null,
+    category varchar(30) not null,
+    created_at date not null default current_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 references courses(id), 
+    title text not null,
+    duration_min int
+)
+
+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 references users(id),
+    course_id int references courses(id),
+    enrolled_at date not null default current_date
+)
+
+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 lessons_views(
+    id int primary key,
+    user_id int references users(id),
+    lesson_id int references lessons(id),
+    viewed_at timestamp not null default now()
+)
+
+insert into lessons_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')

mdrozdov/postgresql/dm_course_summary.sql

@@ -0,0 +1,16 @@
+create materialized view dm_course_summary as
+select
+	e.course_id,
+	c.title,
+	count(distinct e.user_id) as unique_users,
+	count(distinct l.id) as lessons_count,
+	count(distinct lv.id) as total_views,
+	round(count(distinct lv.id)*1.0/nullif(count(distinct e.user_id), 0), 2) as avg_views_per_user,
+	min(lv.viewed_at) as first_viewed_at,
+	max(lv.viewed_at) as last_viewed_at
+from enrollments e
+join courses c on e.course_id = c.id
+join lessons l on  c.id = l.course_id
+join lessons_views lv on lv.lesson_id = l.id
+group by e.course_id, c.title
+order by e.course_id

mdrozdov/postgresql/dm_platform_summary.sql

@@ -0,0 +1,8 @@
+create materialized view dm_platform_summary as
+select 
+	(select count(id) from users) as total_users,
+	(select count(id) from courses) as total_courses,
+	(select count(id) from lessons) as total_lessons,
+	(select count(distinct user_id) from lessons_views) as users_with_views,
+	round((select count(id) from lessons)*1.0/nullif((select count(id) from courses), 0), 2) as avg_lessons_per_course,
+	round((select count(id) from lessons_views)*1.0/nullif((select count(id) from lessons), 0), 2) as avg_views_per_lesson

mdrozdov/postgresql/dm_user_activity_summary.sql

@@ -0,0 +1,84 @@
+CREATE MATERIALIZED VIEW dm_user_activity_summary as 
+with enrollment_counts as(
+	select user_id, 
+		   count(course_id) as enrollment_count
+	from enrollments e
+	group by user_id
+),views as(
+	select user_id, 
+		count(distinct lesson_id) as viewed_lessons_count,
+		min(viewed_at) as first_view, 
+		max(viewed_at) as last_view
+	from lessons_views
+	group by user_id
+), total_lessons as(
+	select 	user_id, 
+			count(*) as total_lessons
+	from enrollments e
+	join lessons using(course_id)
+	group by user_id
+	order by user_id
+), engagment_rate as (
+	select tl.user_id, round(v.viewed_lessons_count*100.0/nullif(total_lessons), 2) as engagment_rate
+	from total_lessons tl
+	join views v using(user_id) 
+)
+select u.id, u.name, enrollment_count, viewed_lessons_count, last_view, first_view, engagment_rate
+from users u
+join enrollment_counts ec on u.id = ec.user_id
+join views v on u.id = v.user_id 
+join engagment_rate er on u.id = er.user_id
+order by u.id
+/*
+--первая попытка сделать витрину, делал избыточно с проверкой каждого подзапроса, поэтому забыл убрать order by, а также больше практиковался в оконных функциях
+CREATE MATERIALIZED VIEW user_activity_summary as
+with enrollment_counts as(
+	select distinct user_id, 
+		   count(course_id) over (partition by user_id) as enrollment_count
+	from enrollments e
+	order by user_id
+), viewed_lessons_count as (
+	select 
+			user_id, count(distinct lesson_id) as viewed_lessons_count
+	from lessons_views lv
+	group by user_id
+	order by user_id
+), first_views as(
+	select 
+			user_id,
+			viewed_at,
+			row_number() over (partition by user_id order by viewed_at asc) as rnf
+	from lessons_views
+), last_views as(
+	select 
+			user_id,
+			viewed_at,
+			row_number() over (partition by user_id order by viewed_at desc) as rnl
+	from lessons_views
+), result_views as(
+	select user_id, 
+		fw.viewed_at as first_view, 
+		lw.viewed_at as last_view
+	from first_views fw
+	join last_views lw using(user_id)
+	where rnf = 1 and rnl = 1
+), total_lessons as(
+	select 	user_id, 
+			count(*) as total_lessons
+	from enrollments e
+	join lessons using(course_id)
+	group by user_id
+	order by user_id
+), engagment_rate as (
+	select tl.user_id, round(vlc.viewed_lessons_count*100.0/total_lessons, 2) as engagment_rate
+	from total_lessons tl
+	join viewed_lessons_count vlc using(user_id) 
+)
+select u.id, u.name, enrollment_count, viewed_lessons_count, last_view, first_view, engagment_rate
+from users u
+join enrollment_counts ec on u.id = ec.user_id
+join viewed_lessons_count vlc on u.id = vlc.user_id
+join result_views rv on u.id = rv.user_id
+join engagment_rate er on u.id = er.user_id
+order by u.id
+*/

ybirk/clickhouse/task_220_&_221.sql

@@ -0,0 +1,278 @@
+CREATE TABLE ybirk.core_user ON CLUSTER clickhouse_cluster
+(
+    user_id Int32,
+    name String,
+    age Int32,
+    email String,
+    registration_date Date
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/core_user',
+    '{replica}'
+)
+ORDER BY user_id;
+
+CREATE TABLE ybirk.core_course ON CLUSTER clickhouse_cluster
+(
+    course_id Int32,
+    title String,
+    category String
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/core_course',
+    '{replica}'
+)
+ORDER BY course_id;
+
+CREATE TABLE ybirk.core_lesson ON CLUSTER clickhouse_cluster
+(
+    lesson_id Int32,
+    title String,
+    duration_min Int32,
+    course_id Int32
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/core_lesson',
+    '{replica}'
+)
+ORDER BY lesson_id;
+
+CREATE TABLE ybirk.core_fact_lesson_views ON CLUSTER clickhouse_cluster
+(
+    user_id Int32, 
+    lesson_id Int32,
+    course_id Int32,
+    viewed_at DateTime64(3)
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/core_fact_lesson_views',
+    '{replica}'
+)
+ORDER BY user_id;
+
+CREATE TABLE ybirk.core_enrollments ON CLUSTER clickhouse_cluster
+(
+    id Int32,
+    user_id Int32,
+    course_id Int32,
+    enrolled_at Date
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/core_enrollments',
+    '{replica}'
+)
+ORDER BY user_id;
+
+--------------------------------
+
+CREATE TABLE ybirk.inactive_users_summary ON CLUSTER clickhouse_cluster
+(
+    user_id UInt32,
+    name String,
+    email String,
+    age UInt8,
+    registered_courses_count UInt32,
+    registration_date DateTime64(3, 'UTC')
+)
+ENGINE = ReplicatedAggregatingMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/inactive_users_summary',
+    '{replica}'
+)
+ORDER BY user_id;
+
+CREATE TABLE ybirk.lesson_popularity_summary ON CLUSTER clickhouse_cluster
+(
+    lesson_id UInt32,
+    lesson_title String,
+    course_id UInt32,
+    course_title String,
+    total_views UInt32,
+    unique_users UInt32,
+    first_view DateTime64(3, 'UTC'),
+    last_view DateTime64(3, 'UTC')
+)
+ENGINE = ReplicatedAggregatingMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/lesson_popularity_summary',
+    '{replica}'
+)
+ORDER BY (lesson_id, course_id);
+
+CREATE TABLE ybirk.course_completion_rate ON CLUSTER clickhouse_cluster
+(
+    user_id UInt32,
+    user_name String,
+    course_id UInt32,
+    course_title String,
+    lessons_in_course UInt32,
+    lessons_viewed UInt32,
+    completion_rate Float32
+)
+ENGINE = ReplicatedAggregatingMergeTree(
+    '/clickhouse/tables/{shard}/ybirk/course_completion_rate',
+    '{replica}'
+)
+ORDER BY (user_id, course_id);
+
+--------------------------------------
+
+CREATE MATERIALIZED VIEW ybirk.mv_lesson_popularity_summary ON CLUSTER clickhouse_cluster
+TO ybirk.lesson_popularity_summary
+AS
+SELECT
+    flv.lesson_id AS lesson_id,
+    l.title AS lesson_title,
+    flv.course_id AS course_id,
+    c.title AS course_title,
+    count() AS total_views,
+    uniqExact(flv.user_id) AS unique_users,
+    min(flv.viewed_at) AS first_view,
+    max(flv.viewed_at) AS last_view
+FROM ybirk.core_fact_lesson_views AS flv
+JOIN ybirk.core_lesson AS l ON flv.lesson_id = l.lesson_id
+JOIN ybirk.core_course AS c ON flv.course_id = c.course_id
+GROUP BY
+    flv.lesson_id,
+    l.title,
+    flv.course_id,
+    c.title;
+
+DROP VIEW IF EXISTS ybirk.mv_inactive_users_summary ON CLUSTER clickhouse_cluster;
+
+CREATE MATERIALIZED VIEW ybirk.mv_inactive_users_summary ON CLUSTER clickhouse_cluster
+TO ybirk.inactive_users_summary
+AS
+SELECT
+    u.user_id AS user_id,
+    u.name AS name,
+    u.email AS email,
+    u.age AS age,
+    countDistinct(e.course_id) AS registered_courses_count,
+    u.registration_date AS registration_date
+FROM ybirk.core_user AS u
+LEFT JOIN ybirk.core_enrollments AS e ON u.user_id = e.user_id
+LEFT ANTI JOIN ybirk.core_fact_lesson_views AS flv ON u.user_id = flv.user_id
+GROUP BY
+    u.user_id,
+    u.name,
+    u.email,
+    u.age,
+    u.registration_date;
+
+CREATE MATERIALIZED VIEW ybirk.mv_course_completion_rate ON CLUSTER clickhouse_cluster
+TO ybirk.course_completion_rate
+AS
+SELECT
+    u.user_id AS user_id,
+    u.name AS user_name,
+    c.course_id AS course_id,
+    c.title AS course_title,
+    countDistinct(l.lesson_id) AS lessons_in_course,
+    countDistinct(flv.lesson_id) AS lessons_viewed,
+    if(countDistinct(l.lesson_id) = 0, 0,
+       round(countDistinct(flv.lesson_id) * 1.0 / countDistinct(l.lesson_id), 2)
+    ) AS completion_rate
+FROM ybirk.core_enrollments AS e
+JOIN ybirk.core_user AS u ON e.user_id = u.user_id
+JOIN ybirk.core_course AS c ON e.course_id = c.course_id
+JOIN ybirk.core_lesson AS l ON c.course_id = l.course_id
+LEFT JOIN ybirk.core_fact_lesson_views AS flv
+    ON flv.user_id = e.user_id
+    AND flv.course_id = e.course_id
+GROUP BY
+    u.user_id,
+    u.name,
+    c.course_id,
+    c.title;
+
+----------------------------------------------
+
+INSERT INTO ybirk.core_user (user_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 ybirk.core_course (course_id, title, category) VALUES
+(1, 'SQL для начинающих', 'data'),
+(2, 'Python для анализа данных', 'programming'),
+(3, 'BI с нуля', 'business');
+
+INSERT INTO ybirk.core_lesson (lesson_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);
+
+INSERT INTO ybirk.core_fact_lesson_views (user_id, lesson_id, course_id, viewed_at) VALUES
+(1, 1, 1, '2023-01-16 10:00:00'),
+(1, 2, 1, '2023-01-16 10:15:00'),
+(2, 1, 1, '2023-01-21 09:00:00'),
+(3, 3, 2, '2023-03-06 12:00:00'),
+(4, 4, 3, '2023-04-02 10:00:00'),
+(4, 5, 3, '2023-04-03 10:00:00');
+
+INSERT INTO ybirk.core_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');    
+
+--------------------------------------------------
+
+--Примеры
+
+SELECT 
+    lesson_title,
+    course_title,
+    total_views
+FROM ybirk.mv_lesson_popularity_summary
+ORDER BY total_views DESC
+LIMIT 5;
+
+SELECT 
+    name,
+    email,
+    registered_courses_count
+FROM ybirk.inactive_users_summary
+WHERE registered_courses_count > 0
+ORDER BY registration_date DESC;
+
+SELECT 
+    course_title,
+    AVG(completion_rate) AS avg_completion
+FROM ybirk.course_completion_rate
+GROUP BY course_title
+ORDER BY avg_completion DESC
+LIMIT 5;
+
+-- ЗАпросы
+
+-- самый популярный курс
+SELECT 
+    course_title, 
+    SUM(total_views) as sum_views
+FROM ybirk.mv_lesson_popularity_summary
+GROUP BY course_title
+ORDER BY sum_views DESC;
+
+
+-- Кто застрял
+SELECT 
+    user_name, 
+    course_title,
+    completion_rate
+FROM ybirk.mv_course_completion_rate
+WHERE completion_rate > 0 AND completion_rate < 1.0;
+
+-- тест3
+SELECT 
+    t1.user_name,
+    t1.course_title,
+    t2.email
+FROM ybirk.mv_course_completion_rate AS t1
+JOIN ybirk.mv_inactive_users_summary AS t2 
+    ON t1.user_id = t2.user_id
+WHERE t1.completion_rate = 1.0;