每个排序规则必须有一个唯一的 ID。要添加排序规则，您必须选择一个当前未使用的 ID 值。MySQL 支持双字节排序规则 ID。ID 范围从 1024 到 2047 保留给用户自定义排序规则。Each collation must have a unique ID. To add a collation, you must choose an ID value that is not currently used. MySQL supports two-byte collation IDs. The range of IDs from 1024 to 2047 is reserved for user-defined collations.

您选择的排序规则 ID 会出现在以下上下文中：The collation ID that you choose appears in these contexts:

要确定当前使用的最大 ID，请发出以下语句：To determine the largest currently used ID, issue the following statement:

mysql> SELECT MAX(ID) FROM INFORMATION_SCHEMA.COLLATIONS;
+---------+
| MAX(ID) |
+---------+
|     247 |
+---------+

要显示所有当前使用的 ID 列表，请发出此语句：To display a list of all currently used IDs, issue this statement:

mysql> SELECT ID FROM INFORMATION_SCHEMA.COLLATIONS ORDER BY ID;
+-----+
| ID  |
+-----+
|   1 |
|   2 |
| ... |
|  52 |
|  53 |
|  57 |
|  58 |
| ... |
|  98 |
|  99 |
| 128 |
| 129 |
| ... |
| 247 |
+-----+