我使用下表来存储产品数据:
mysql> SELECT * FROM product;
+---------------+---------------+--------+
| id | name | description | stock |
+---------------+---------------+--------+
| 1 | product1 | first product | 5 |
| 2 | product2 | second product| 5 |
+---------------+---------------+--------+
mysql> SELECT * FROM product_additional;
+-----------------+------------+
| id | fieldname | fieldvalue |
+-----------------+------------+
| 1 | size | S |
| 1 | height | 103 |
| 2 | size | L |
| 2 | height | 13 |
| …