問1
CREATE TABLE item_category(category_id INT AUTO_INCREMENT, category_name VARCHAR(256) NOT NULL, PRIMARY KEY (category_id));

INSERT INTO item_category (category_name) VALUES ('家具');
INSERT INTO item_category (category_name) VALUES ('飲料');
INSERT INTO item_category (category_name) VALUES ('食品');

問2
CREATE TABLE items(item_id INT AUTO_INCREMENT, name VARCHAR(256) NOT NULL, price INT NOT NULL, category_id INT, PRIMARY KEY (item_id));

ALTER TABLE items ADD FOREIGN KEY(category_id) REFERENCES item_category(category_id);

INSERT INTO items(name, price, category_id) VALUES('ローマのテーブル', 150000, 1);
INSERT INTO items(name, price, category_id) VALUES('げーたるーど2000 500ml', 370, 2);
INSERT INTO items(name, price, category_id) VALUES('原子肉', 2500, 3);
INSERT INTO items(name, price, category_id) VALUES('魅惑の椅子', 100000, 1);

問3
SELECT item_category.category_id, items.item_id, items.name,items.price, item_category.category_name AS name FROM item_category INNER JOIN items ON item_category.category_id = items.category_id;

問4
SELECT item_category.category_id, items.item_id, items.name,items.price, item_category.category_name AS name FROM item_category INNER JOIN items ON item_category.category_id = items.category_id ORDER BY items.price ASC;

問5
SELECT item_category.category_id, items.item_id, items.name,items.price, item_category.category_name AS name FROM item_category INNER JOIN items ON item_category.category_id = items.category_id WHERE item_category.category_name = '家具';

問6
SELECT item_category.category_id, items.item_id, items.name,items.price, item_category.category_name AS name FROM item_category INNER JOIN items ON item_category.category_id = items.category_id WHERE price >= 1000 AND price <= 50000;

問7
SELECT COUNT(*) AS data_count FROM items;

問8
SELECT item_category.category_id, items.item_id, items.name,items.price, item_category.category_name AS name FROM item_category INNER JOIN items ON item_category.category_id = items.category_id WHERE price = (SELECT MAX(price) FROM items);

問9
SELECT item_category.category_id, items.item_id, items.name,items.price, item_category.category_name AS name FROM item_category INNER JOIN items ON item_category.category_id = items.category_id WHERE name LIKE '%の%';