Решение по базовый SQL

ebelykh/postgresql/базовый SQL/Select.sql

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+--Задача 1757
+SELECT product_id
+FROM Products
+WHERE low_fats = 'Y' AND recyclable = 'Y';
+
+--Задача 584
+SELECT name
+FROM Customer
+WHERE referee_id!= 2 OR referee_id IS NULL;
+
+--Задача 595
+SELECT name, population, area
+FROM World
+WHERE area >= 3000000
+   OR population >= 25000000;
+
+--Задача 1148 
+SELECT DISTINCT author_id AS id
+FROM Views
+WHERE author_id = viewer_id
+ORDER BY id; 
+
+--Задача 1683 
+SELECT tweet_id
+FROM Tweets
+WHERE CHAR_LENGTH(content) > 15;
+
+--Задача 620
+SELECT id, movie, description, rating
+FROM Cinema
+WHERE id % 2 = 1
+  AND description != 'boring'
+ORDER BY rating DESC;
+
+--Задача 1667
+SELECT
+  user_id,
+  CONCAT(
+    UPPER(SUBSTR(name, 1, 1)),
+    LOWER(SUBSTR(name, 2))
+  ) AS name
+FROM Users
+ORDER BY user_id;

ebelykh/postgresql/основы SQL/Script.sql

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+--Задача 1
+  CREATE TABLE products_extended (
+  id INT PRIMARY KEY,
+  name VARCHAR(100) NOT NULL,
+  category VARCHAR(50),
+  price DECIMAL(6,2),
+  in_stock BOOLEAN DEFAULT true,
+  email_support VARCHAR
+);
+
+
+--Задача 2 Вариант с DEFAULT (in_stock не указываем)
+INSERT INTO products_extended (id, name, category, price, email_support)
+VALUES
+(1, 'Mi Band 7', 'smartwatch', 49.00, 'miband@xiaomi.com'),
+(2, 'Surface Pro', 'tablet', 1299.00, 'surface@microsoft.com');
+
+--Задача 3
+ALTER TABLE products_extended  
+ADD COLUMN rating DECIMAL(3,2), 
+DROP COLUMN email_support;
+
+--Задача 4
+UPDATE products_extended
+SET price = price * 1.1
+WHERE name = 'Mi Band 7';
+
+--Задача 5(удаляет данные/таблицу)
+TRUNCATE TABLE products_extended;
+DROP TABLE products_extended;
+
+
+

ebelykh/postgresql/фильтрация/Script.sql

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+SELECT
+ name,
+ category,
+  price,
+  price * 1.10 AS price_with_markup,
+  price * 1.20 AS price_with_vat,
+  COALESCE(email_support, 'нет почты') AS status
+FROM products_extended
+WHERE in_stock = true
+  AND category NOT IN ('smartwatch', 'ebook_reader')
+  AND price BETWEEN 300 AND 1300;
+
+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;
+