MariaDB 10.0.X中，动态列支持 JSON 格式来获取数据

MariaDB 10.0.X中，动态列（Dynamic Columns），可以支持 JSON 格式来获取数据。 为了兼容传统SQL语法，MariaDB 10和MySQL5.7支持

mysql> UPDATE assets SET dynamic_cols=COLUMN_ADD(dynamic_cols, 'warranty', '3 years')

-> WHERE item_name='Thinkpad Laptop';

Query OK, 1 row affected (0.01 sec)

Rows matched: 1 Changed: 1 Warnings: 0

mysql> SELECT item_name, COLUMN_JSON(dynamic_cols) FROM assets;

+-----------------+----------------------------------------+

| item_name | COLUMN_JSON(dynamic_cols) |

+-----------------+----------------------------------------+

| MariaDB T-shirt | {"size":"XL","color":"blue"} |

| Thinkpad Laptop | {"color":"black","warranty":"3 years"} |

+-----------------+----------------------------------------+

2 rows in set (0.00 sec)