pavel
158 lines
2.9 KiB
SQL
158 lines
2.9 KiB
SQL
/* 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'; |