Q2終わりました

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2026-09-28 13:40:51 +09:00
parent c9e5e80e6b
commit 760ccf0169

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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 (0.01 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 (0.01 sec)
mysql> INSERT INTO items VALUES (3, '原始肉', 2500, 3);l
Query OK, 1 row affected (0.01 sec)
-> INSERT INTO items VALUES (4, '魅惑の椅子', 100000, 1);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'l
INSERT INTO items VALUES (4, '魅惑の椅子', 100000, 1)' at line 1
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 (0.01 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 |
| 3 | 原始肉 | 2500 | 3 |
| 4 | 魅惑の椅子 | 100000 | 1 |
+---------+------------------------+--------+-------------+
5 rows in set (0.00 sec)
mysql> DELETE FROM items WHERE item_id = 3;
Query OK, 2 rows affected (0.00 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 |
| 4 | 魅惑の椅子 | 100000 | 1 |
+---------+------------------------+--------+-------------+
3 rows in set (0.00 sec)
mysql> INSERT INTO items VALUES (3, '原始肉', 2500, 3);
Query OK, 1 row affected (0.01 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 |
| 4 | 魅惑の椅子 | 100000 | 1 |
| 3 | 原始肉 | 2500 | 3 |
+---------+------------------------+--------+-------------+
4 rows in set (0.00 sec)
mysql> DELETE FROM items WHERE item_id = 4;
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO items VALUES (4, '魅惑の椅子', 100000, 1);
Query OK, 1 row affected (0.01 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 (0.00 sec)
mysql> SELECT items.category_id, items.item_id, items.name, items.price, item_category.category_name FROM items INNER JOIN item_category ON items.category_id = item_category.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 items.category_id, items.item_id, items.name, items.price, item_category.category_name FROM items INNER JOIN item_category ON items.category_id = item_category.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 items.category_id, items.item_id, items.name, items.price, item_category.category_name FROM items INNER JOIN item_category ON items.category_id = item_category.category_id AND items.category_id = 1;
+-------------+---------+------------------+--------+---------------+
| 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 items.category_id, items.item_id, items.name, items.price, item_category.category_name FROM items INNER JOIN item_category ON items.category_id = item_category.category_id AND 1000 <= items.price AND items.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 (0.00 sec)
mysql> CREATE TABLE items_category AS SELECT items.category_id, items.item_id, items.name, items.price, item_category.category_name FROM items INNER JOIN item_category ON items.category_id = item_category.category_id ORDER BY price ASC;
Query OK, 4 rows affected (0.03 sec)
Records: 4 Duplicates: 0 Warnings: 0
mysql> SELECT * FROM items_category WHERE price = (SELECT MAX(price) FROM items_category);
+-------------+---------+------------------+--------+---------------+
| 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 items_category WHERE name LIKE '%の%';
+-------------+---------+------------------+--------+---------------+
| category_id | item_id | name | price | category_name |
+-------------+---------+------------------+--------+---------------+
| 1 | 4 | 魅惑の椅子 | 100000 | 家具 |
| 1 | 1 | ローマのテーブル | 150000 | 家具 |
+-------------+---------+------------------+--------+---------------+
2 rows in set (0.00 sec)