Merge pull request 'test commit' (#36) from anton into main

Reviewed-on: https://gitea.de-infra.servehttp.com/de-infrastructure/DWH/pulls/36
2026-01-17 16:47:30 +04:00
parent 08e09f7515 c4550632f0
commit 1a608757b2
32 changed files with 244 additions and 0 deletions
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 /*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
@@ -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;
@@ -0,0 +1 @@
 CREATE TABLE test_db;#
@@ -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;