diff --git a/amaksatov/postgresql/OS-329.sql b/amaksatov/postgresql/OS-329.sql
new file mode 100644
index 0000000..3f0f080
--- /dev/null
+++ b/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'
+);
+
diff --git a/amaksatov/postgresql/OS-330.sql b/amaksatov/postgresql/OS-330.sql
new file mode 100644
index 0000000..9b78b52
--- /dev/null
+++ b/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;