dr0zd
136 lines
4.2 KiB
SQL
136 lines
4.2 KiB
SQL
CREATE TABLE mdrozdov.users (
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user_id Int,
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name String,
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age Int,
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country String,
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is_active bool
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)
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engine = MergeTree
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order by user_id
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insert into mdrozdov.users values
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(1, 'Ivan' ,30, 'RU', 1),
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(2, 'Anna' ,25, 'RU', 1),
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(3, 'Petr' ,45, 'RU', 0),
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(4, 'Olga' ,35, 'RU', 1),
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(5, 'John' ,55, 'US', 1),
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(6, 'Alice' ,42, 'US', 0),
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(7, 'Tom' ,38, 'US', 1),
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(8, 'Lucas' ,28, 'BR', 1),
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(9, 'Maria' ,60, 'BR', 1),
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(10, 'João' ,27, 'BR', 0),
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(11, 'Kenji' ,33, 'JP', 1),
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(12, 'Yuki' ,29, 'JP', 0),
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(13, 'Chen' ,40, 'CN', 1),
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(14, 'Li' ,48, 'CN', 1),
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(15, 'Fatima',31, 'AE', 1),
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(16, 'Ahmed' ,36, 'AE', 1),
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(17, 'George',24, 'US', 1),
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(18, 'Nina' ,34, 'RU', 1),
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(19, 'Max' ,50, 'DE', 1),
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(20, 'Sophie',22, 'DE', 0)
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--1. Получи 10 самых старших **активных** пользователей.
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select
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user_id,
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name,
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age,
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country,
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is_active
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from mdrozdov.users
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where is_active
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order by age desc
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limit 10
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--2. Выведи пользователей из `country = 'RU'`, отсортированных по имени.
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select
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user_id,
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name,
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age,
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country,
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is_active
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from mdrozdov.users
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where country = 'RU'
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order by name asc
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--3. Что произойдёт, если написать `LIMIT 10` **без `ORDER BY`**?
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-- ответ будет недетерминирован
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--4. Посчитай количество пользователей по странам.
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select
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country,
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count(user_id) as total_users
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from mdrozdov.users
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group by country
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--5. Для каждой страны выведи минимальный и максимальный возраст.
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select
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country,
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min(age) as min_user_age,
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max(age) as max_user_age
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from mdrozdov.users
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group by country
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--6. Отсортируй страны по убыванию количества пользователей.
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select
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country,
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count(user_id) as total_users
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from mdrozdov.users
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group by country
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order by total_users desc
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-- task 2
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CREATE TABLE mdrozdov.events (
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user_id Int,
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event_time DateTime,
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event_type String --mb better enum but idc
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)
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engine = MergeTree
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order by user_id
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insert into events values
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(1, '2025-07-17 09:00:00', 'click'),
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(1, '2025-07-17 09:05:00', 'view'),
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(1, '2025-07-17 09:10:00', 'purchase'),
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(2, '2025-07-17 10:00:00', 'click'),
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(2, '2025-07-17 10:05:00', 'click'),
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(2, '2025-07-17 11:00:00', 'view'),
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(3, '2025-07-16 12:00:00', 'view'),
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(3, '2025-07-16 12:30:00', 'click'),
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(3, '2025-07-17 08:00:00', 'purchase'),
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(4, '2025-07-17 13:00:00', 'click'),
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(4, '2025-07-17 14:00:00', 'view'),
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(4, '2025-07-17 15:00:00', 'view'),
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(5, '2025-07-16 20:00:00', 'view'),
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(5, '2025-07-17 01:00:00', 'click'),
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(5, '2025-07-17 06:00:00', 'purchase'),
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(6, '2025-07-17 07:30:00', 'view'),
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(6, '2025-07-17 08:45:00', 'click'),
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(7, '2025-07-16 23:59:59', 'click'),
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(7, '2025-07-17 00:01:00', 'purchase'),
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(7, '2025-07-17 10:10:00', 'view')
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--1-2) Добавь колонку с кумулятивным количеством событий по user_id (используй count() OVER ...)
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select
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user_id,
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event_time,
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event_type,
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count(*) over (partition by user_id order by event_time) as total_click_exact_moment,
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row_number() over (partition by user_id order by event_time) as row_number
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from mdrozdov.events
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--3) да, поддерживается, но не обязательно для коммулятивного суммирования строк
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--4-6) Сделай WITH recent_events AS (...) — все события за последние 24 часа.
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with mdrozdov.recent_events AS (
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select *
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from mdrozdov.events
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where event_time >= toDateTime('2025-07-18') - interval 1 day
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), category_list as (
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select 'click' as event_type, 'interaction' as category
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union all
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select 'view', 'interaction'
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union all
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select 'purchase', 'conversion'
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)
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select
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user_id,
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count(*) as total_events_last_24h,
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count(distinct cl.category) as uniq_categories
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from recent_events re
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left join category_list cl
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using(event_type)
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group by user_id
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order by total_events_last_24h desc, user_id asc
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limit 5 |