mysql> CREATE TABLE item_category (category_id INT,category_name VARCHAR(256));
Query OK, 0 rows affected (0.02 sec)

mysql> INSERT INTO item_category VALUES (1,'家具');
Query OK, 1 row affected (0.00 sec)

mysql>  INSERT INTO item_category VALUES (2,'飲料');
Query OK, 1 row affected (0.00 sec)

mysql>  INSERT INTO item_category VALUES (3,'食品');
Query OK, 1 row affected (0.05 sec)

mysql> SELECT * FROM item_category;
+-------------+---------------+
| category_id | category_name |
+-------------+---------------+
|           1 | 家具          |
|           2 | 飲料          |
|           3 | 食品          |
+-------------+---------------+
3 rows in set (0.00 sec)

mysql> CREATE TABLE items(item_id INT, name VARCHAR(256), price INT, category_id INT);
Query OK, 0 rows affected (0.02 sec)

mysql> INSERT INTO items VALUES (1,'ローマのテーブル', 150000, 1);
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO items VALUES (2,'げーたるーど2000 500ml', 370, 2);
Query OK, 1 row affected (0.00 sec)

mysql>  INSERT INTO items VALUES (3,'原始肉', 2500, 3);
Query OK, 1 row affected (0.00 sec)

mysql>  INSERT INTO items VALUES (4,'魅惑の椅子', 100000, 1);
Query OK, 1 row affected (0.05 sec)

mysql> SELECT * FROM items;
+---------+------------------------+--------+-------------+
| item_id | name                   | price  | category_id |
+---------+------------------------+--------+-------------+
|       1 | ローマのテーブル       | 150000 |           1 |
|       2 | げーたるーど2000 500ml |    370 |           2 |
|       3 | 原始肉                 |   2500 |           3 |
|       4 | 魅惑の椅子             | 100000 |           1 |
+---------+------------------------+--------+-------------+
4 rows in set (0.05 sec)

mysql>  SELECT * FROM item_category LEFT JOIN items USING(category_id);
+-------------+---------------+---------+------------------------+--------+
| category_id | category_name | item_id | name                   | price  |
+-------------+---------------+---------+------------------------+--------+
|           1 | 家具          |       4 | 魅惑の椅子             | 100000 |
|           1 | 家具          |       1 | ローマのテーブル       | 150000 |
|           2 | 飲料          |       2 | げーたるーど2000 500ml |    370 |
|           3 | 食品          |       3 | 原始肉                 |   2500 |
+-------------+---------------+---------+------------------------+--------+
4 rows in set (0.00 sec)

mysql> SELECT * FROM item_category RIGHT JOIN items USING(category_id);
+-------------+---------+------------------------+--------+---------------+
| category_id | item_id | name                   | price  | category_name |
+-------------+---------+------------------------+--------+---------------+
|           1 |       1 | ローマのテーブル       | 150000 | 家具          |
|           2 |       2 | げーたるーど2000 500ml |    370 | 飲料          |
|           3 |       3 | 原始肉                 |   2500 | 食品          |
|           1 |       4 | 魅惑の椅子             | 100000 | 家具          |
+-------------+---------+------------------------+--------+---------------+
4 rows in set (0.00 sec)

mysql> SELECT * FROM item_category RIGHT JOIN items USING(category_id) ORDER BY price ASC;
+-------------+---------+------------------------+--------+---------------+
| category_id | item_id | name                   | price  | category_name |
+-------------+---------+------------------------+--------+---------------+
|           2 |       2 | げーたるーど2000 500ml |    370 | 飲料          |
|           3 |       3 | 原始肉                 |   2500 | 食品          |
|           1 |       4 | 魅惑の椅子             | 100000 | 家具          |
|           1 |       1 | ローマのテーブル       | 150000 | 家具          |
+-------------+---------+------------------------+--------+---------------+
4 rows in set (0.00 sec)

mysql>  SELECT * FROM item_category RIGHT JOIN items USING(category_id) where category_name = '家具';
+-------------+---------+------------------+--------+---------------+
| category_id | item_id | name             | price  | category_name |
+-------------+---------+------------------+--------+---------------+
|           1 |       1 | ローマのテーブル | 150000 | 家具          |
|           1 |       4 | 魅惑の椅子       | 100000 | 家具          |
+-------------+---------+------------------+--------+---------------+
2 rows in set (0.00 sec)

mysql>  SELECT * FROM item_category RIGHT JOIN items USING(category_id) where price > 1000 AND price < 50000;
+-------------+---------+--------+-------+---------------+
| category_id | item_id | name   | price | category_name |
+-------------+---------+--------+-------+---------------+
|           3 |       3 | 原始肉 |  2500 | 食品          |
+-------------+---------+--------+-------+---------------+
1 row in set (0.00 sec)

mysql>  SELECT COUNT(*) AS data_count FROM items;
+------------+
| data_count |
+------------+
|          4 |
+------------+
1 row in set (0.01 sec)

mysql>  SELECT * FROM item_category RIGHT JOIN items USING(category_id) WHERE price = (SELECT MAX(price) FROM items);
+-------------+---------+------------------+--------+---------------+
| category_id | item_id | name             | price  | category_name |
+-------------+---------+------------------+--------+---------------+
|           1 |       1 | ローマのテーブル | 150000 | 家具          |
+-------------+---------+------------------+--------+---------------+
1 row in set (0.00 sec)

mysql>  SELECT * FROM item_category RIGHT JOIN items USING(category_id) WHERE name LIKE '%の%';
+-------------+---------+------------------+--------+---------------+
| category_id | item_id | name             | price  | category_name |
+-------------+---------+------------------+--------+---------------+
|           1 |       1 | ローマのテーブル | 150000 | 家具          |
|           1 |       4 | 魅惑の椅子       | 100000 | 家具          |
+-------------+---------+------------------+--------+---------------+
2 rows in set (0.00 sec)