join tasks done
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pavel
@@ -1,188 +0,0 @@
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CREATE TABLE users (
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id int PRIMARY KEY, -- NOT NULL
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name varchar(100) NOT NULL,
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age int,
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email varchar(100),
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country varchar(2),
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is_active boolean,
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created_at timestamptz NOT NULL
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);
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CREATE TABLE products (
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id int PRIMARY KEY,
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name varchar(100) NOT NULL,
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category varchar(50),
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price decimal(10,2) NOT NULL,
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in_stock BOOLEAN -- или int, потому что или на складе или не на складе
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);
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CREATE TABLE orders (
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id int PRIMARY KEY,
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user_id int,
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order_date timestamptz NOT NULL,
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status varchar(20)
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);
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CREATE TABLE order_items (
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order_id int,
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product_id int,
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quantity int NOT NULL,
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price_at_purchase decimal(10,2) NOT NULL,
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PRIMARY KEY (order_id, product_id)
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);
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INSERT INTO pmikhailov.users
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(id, "name", age, email, country, is_active, created_at) VALUES
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(1, 'Alice', 25, 'alice@example.com', 'US', TRUE, '2024-01-10 10:00:00'),
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(2, 'Bob', 30, 'bob@example.com', 'UK', TRUE, '2024-02-05 09:30:00'),
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(3, 'Carol', 27, 'carol@example.com', 'US', FALSE, '2024-03-01 15:20:00'),
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(4, 'Diana', 22, 'diana@gmail.com', 'US', TRUE, '2024-01-12 08:15:00'),
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(5, 'Evan', 35, 'evan@example.com', 'UK', TRUE, '2024-01-18 19:40:00'),
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(6, 'Farida', 29, 'farida@example.com', 'KZ', TRUE, '2024-02-20 11:05:00'),
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(7, 'George', 31, 'george+test@example.com', 'US', TRUE, '2024-03-05 16:45:00'),
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(8, 'Helen', 24, NULL, 'UK', FALSE, '2024-03-06 08:20:00'),
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(9, 'Ivan', 26, 'ivan@example.com', 'RU', TRUE, '2024-01-11 14:30:00'),
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(10, 'Julia', 28, 'julia@example.com', 'US', TRUE, '2024-03-07 18:05:00');
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INSERT INTO pmikhailov.products
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(id, "name", category, price, in_stock) VALUES
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(1, 'iPhone 15', 'Электроника', 80000, TRUE),
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(2, 'Kindle', 'Электроника', 15000, TRUE),
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(3, 'Кроссовки Nike', 'Одежда', 9000, TRUE),
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(4, 'Кроссовки NoName', 'Одежда', 3000, FALSE),
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(5, 'Наушники Pro', 'Электроника', 12000, TRUE),
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(6, 'Фитнес-браслет', 'Гаджеты', 6000, TRUE),
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(7, 'Подарочная карта', 'Сервисы', 1000, TRUE);
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INSERT INTO pmikhailov.orders
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(id, user_id, order_date, status) VALUES
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(1, 1, '2025-01-10 12:00:00', 'paid'),
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(2, 3, '2025-01-12 09:30:00', 'cancelled'),
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(3, 1, '2025-01-15 18:20:00', 'paid'),
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(4, 2, '2025-01-20 11:05:00', 'created'),
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(5, 4, '2025-02-01 17:45:00', 'paid'),
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(6, 5, '2025-02-10 10:10:00', 'refunded'),
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(7, 7, '2025-03-01 09:00:00', 'paid'),
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(8, 9, '2025-03-05 19:30:00', 'paid');
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INSERT INTO pmikhailov.order_items
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(order_id, product_id, quantity, price_at_purchase) VALUES
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(1, 1, 1, 78000),
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(1, 3, 2, 8500),
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(2, 2, 1, 14000),
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(3, 5, 1, 11000),
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(3, 7, 1, 1000),
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(4, 2, 1, 15000),
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(5, 6, 1, 6000),
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(6, 1, 1, 82000),
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(7, 3, 1, 9000),
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(8, 4, 2, 2800);
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SELECT id, name, country, created_at, email
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FROM users
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ORDER BY created_at DESC, name ASC;
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SELECT id, name, country
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FROM users
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WHERE country = 'US'
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ORDER BY name ASC;
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SELECT id, name, country
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FROM users
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WHERE country = 'UK'
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ORDER BY name ASC;
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SELECT id, name, email
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FROM users u
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WHERE email IS NOT NULL
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ORDER BY name ASC;
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SELECT DISTINCT lower(email)
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FROM users u
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WHERE email IS NOT null;
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SELECT id, name, created_at
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FROM users
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WHERE created_at >= '2024-02-05 09:30:00.000 +0100'
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ORDER BY created_at DESC
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LIMIT 2 OFFSET 1;
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/* Задача 1 */
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SELECT
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name,
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category,
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price,
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price * 1.3 AS price_with_markup,
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price * 1.5 AS price_with_vat
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FROM
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products p
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WHERE
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in_stock IS TRUE
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AND price BETWEEN 100 AND 1300;
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/* Задача 2 */
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SELECT
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name,
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price,
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price * 0.85 AS price_with_discount
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FROM
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products p
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WHERE
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(price <= 100) OR (price >= 1000);
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/* Задача 3 */
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SELECT
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id,
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name,
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category,
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price
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FROM
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products p
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WHERE
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category IN ('tablet', 'smartphone', 'mouse')
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AND price >= 100;
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/* Задача 4 */
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SELECT
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name,
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category,
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price
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FROM
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products p
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WHERE name NOT ILIKE '%iPhone%';
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/* Задача 5 */
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SELECT
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name,
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category,
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price
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FROM
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products p
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WHERE
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name NOT ILIKE '%pro%'
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ORDER BY
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price DESC;
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SELECT
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name,
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category,
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price
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FROM
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products p
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WHERE
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name NOT ILIKE '%mx%';
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ORDER BY
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price DESC;
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@@ -0,0 +1,158 @@
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/* Задача 1
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* Джойним в таком порядке т.к. не каждый юзер делал заказ
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* + судя по порядку колонок мы хотим анализировать заказы
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* (по сути выглядит так же как INNER)
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* Но в обратном порядке можем увидеть кто не делал заказ
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* и добавить их в условную рассылку
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*/
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SELECT
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o.id AS order_id,
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o.order_date,
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status,
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u."name" AS user_name,
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country
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FROM
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orders o
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LEFT JOIN
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users u ON o.user_id = u.id
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/* Задача 2 */
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SELECT
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order_id,
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p."name" AS product_name,
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quantity,
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price_at_purchase
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FROM
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order_items oi
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LEFT JOIN
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products p ON oi.product_id = p.id -- AND oi.order_id = 1 из правой таблицы будут NULL там, где оба условия не выполнены
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WHERE order_id = 1 -- в задании другой номер - 101, надо исправить в Notion, данные на п.4 уже другие
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/* Задача 3 */
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SELECT
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order_id,
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u."name" AS user_name,
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p."name" AS product_name,
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quantity,
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price_at_purchase
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FROM
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orders o
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LEFT JOIN
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order_items oi ON o.id = oi.order_id
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INNER JOIN
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users u ON o.id = u.id
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INNER JOIN
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products p ON oi.product_id = p.id;
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/* Задача 4 */
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SELECT
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u."name" AS user_name,
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o.id AS order_id,
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status
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FROM
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users u
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LEFT JOIN
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orders o ON u.id = o.user_id
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/* Задача 5 */
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SELECT
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o.user_id,
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u."name" AS user_name
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FROM
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users u
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LEFT JOIN
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orders o ON u.id = o.id
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WHERE o.user_id IS NOT NULL
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/* Задача 6 */
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SELECT
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o.id AS order_id,
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u.name AS user_name,
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p.name AS product_name,
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quantity
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FROM
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orders o
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LEFT JOIN
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order_items oi ON o.id = oi.order_id
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INNER JOIN
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products p ON oi.product_id = p.id
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INNER JOIN
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users u ON o.user_id = u.id
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WHERE p."name" ILIKE '%Mi Band 7%';
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/* Задача 7 */
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SELECT
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p.name AS product_name,
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order_id,
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quantity
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FROM
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products p
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FULL JOIN
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order_items oi ON p.id = oi.product_id
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ORDER BY product_name;
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/* Задача 8 */
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SELECT
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o.id,
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u."name" AS user_name,
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p."name" AS product_name,
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quantity,
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price_at_purchase
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FROM
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orders o
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LEFT JOIN
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order_items oi ON o.id = oi.order_id
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INNER JOIN
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users u ON o.user_id = u.id
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LEFT JOIN
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products p ON oi.product_id = p.id
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WHERE
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o.status = 'paid';
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/* Задача 9 */
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SELECT
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o.id AS order_id,
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o.order_date,
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p."name" AS product_name,
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quantity,
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price_at_purchase
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FROM
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orders o
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LEFT JOIN
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order_items oi ON o.id = oi.order_id
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INNER JOIN
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products p ON oi.product_id = p.id
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INNER JOIN
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users u ON o.user_id = u.id
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WHERE u."name" ILIKE '%alice%';
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/* Задача 10
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* Задача противоречит изначальным органичениям NOT NULL
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*/
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SELECT
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o.id AS order_id,
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user_id,
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status
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FROM
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orders o
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FULL JOIN
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order_items oi ON oi.order_id = o.id
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WHERE product_id IS NULL AND o.status = 'created';
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