Question

我正在尝试向现有数据库添加一个列以存储UUID，然后检索具有该记录的UUID的行，但我一直得到一个空集。我创建了列作为BINARY（64），因为当我尝试BINARY（16）时，有些站点建议，它不足以保存数据。这是我的创建声明：

ALTER TABLE `my_table`  ADD `email_uuid` BINARY(64) NULL,  ADD UNIQUE (`email_uuid`)

然后我填充了它：

UPDATE `my_table` SET `email_uuid` = UUID();

为了测试它，我查询了表以获取UUID：

mysql> select emailaddr,email_uuid FROM my_table WHERE emailaddr = 'myemail@mydomain.com';
+------------------------------------------+------------------------------------------+
| emailaddr                                | email_uuid                               |
+------------------------------------------+------------------------------------------+
| myemail@mydomain.com | a332f4d4-ddb2-11e2-88f9-80ee731fd7a1     |
+------------------------------------------+------------------------------------------+

我已经尝试了几种不同的方法来恢复该行：

mysql> select emailaddr,email_uuid FROM my_table WHERE email_uuid = 'a332f4d4-ddb2-11e2-88f9-80ee731fd7a1';
Empty set (0.00 sec)

mysql> select emailaddr,email_uuid FROM my_table WHERE email_uuid = '{a332f4d4ddb211e288f980ee731fd7a1}';
Empty set (0.00 sec)

mysql> select emailaddr,email_uuid FROM my_table WHERE email_uuid = BIN('{a332f4d4ddb211e288f980ee731fd7a1}');
Empty set (0.02 sec)

mysql> select emailaddr,email_uuid FROM my_table WHERE email_uuid = '61333332663464342d646462322d313165322d383866392d38306565373331666437613100000000';
Empty set (0.00 sec)

mysql> select emailaddr,email_uuid FROM my_table WHERE email_uuid = UNHEX(REPLACE('a332f4d4-ddb2-11e2-88f9-80ee731fd7a1','-',''));
Empty set (0.02 sec)

我有什么遗失的吗？

Answer 1

UUID字符串长度为36 个字节。通过这种微小的变化，它对我来说就像一个魅力：

mysql> create table U (`email_uuid` BINARY(36)):
Query OK, 0 rows affected (0.34 sec)

mysql> insert into U VALUES ( 'a332f4d4-ddb2-11e2-88f9-80ee731fd7a1' ):
Query OK, 1 row affected (0.01 sec)

mysql> select * from U where `email_uuid` = 'a332f4d4-ddb2-11e2-88f9-80ee731fd7a1':
+--------------------------------------+
| email_uuid                           |
+--------------------------------------+
| a332f4d4-ddb2-11e2-88f9-80ee731fd7a1 |
+--------------------------------------+
1 row in set (0.00 sec)

在表中添加和查找UUID

1 个答案: