mysql - mysql表中插入emoji字符的一些令人困惑的现象

Question

在mysql交互界面中插入emoji字符时，我发现一些现象非常令人困惑。希望有人可以清除它。现在请看下面:

mysql> show variables like 'character%';
+--------------------------+---------------------------------------+
| Variable_name            | Value                                 |
+--------------------------+---------------------------------------+
| character_set_client     | utf8                                  |
| character_set_connection | utf8                                  |
| character_set_database   | latin1                                |
| character_set_filesystem | binary                                |
| character_set_results    | utf8                                  |
| character_set_server     | latin1                                |
| character_set_system     | utf8                                  |
| character_sets_dir       | /opt/mysql/server-5.6/share/charsets/ |
+--------------------------+---------------------------------------+
CREATE TABLE `t` (
`data` varchar(100) CHARACTER SET utf8mb4 DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
mysql> insert into t select '\U+1F600';
ERROR 1366 (HY000): Incorrect string value: '\xF0\x9F\x98\x80' for column 'data' at row 1
mysql> set names utf8mb4;
mysql> insert into t select '\U+1F600';
Query OK, 1 row affected (0.00 sec)
mysql> select * from t;
+------+
| data |
+------+
| 😀     |
+------+
mysql> select data, hex(data) from t;
+------+-----------+
| data | hex(data) |
+------+-----------+
| 😀     | F09F9880  |
+------+-----------+

为什么我需要显式执行集合名称 utf8mb4？从错误信息来看，似乎成功地将数据内容解析为四个字节(f0 9f 98 80)？为什么还是无法插入成功？

下面是我的另一个难题。

mysql> show variables like 'character%';
+--------------------------+---------------------------------------+
| Variable_name            | Value                                 |
+--------------------------+---------------------------------------+
| character_set_client     | latin1                                |
| character_set_connection | latin1                                |
| character_set_database   | latin1                                |
| character_set_filesystem | binary                                |
| character_set_results    | latin1                                |
| character_set_server     | latin1                                |
| character_set_system     | utf8                                  |
| character_sets_dir       | /opt/mysql/server-5.6/share/charsets/ |
+--------------------------+---------------------------------------+
mysql> insert into t select '\U+1F600';
Query OK, 1 row affected (0.01 sec)
mysql> select data,hex(data) from t;
+------+--------------------+
| data | hex(data)          |
+------+--------------------+
| 😀     | C3B0C5B8CB9CE282AC |
+------+--------------------+

我不得不说我对此感到有点震惊。在我看来，只有 utf8mb4 支持表情符号字符，但现在 latin1 也支持表情符号字符。任何人都可以帮我清除。谢谢!

Answer 1

您可以将UTF8数据插入latin1表中，但MySQL不会将字节流视为UTF8字符。因此，您将无法对其进行查询。如果您的应用程序能够理解 UTF8 字节流，那么它看起来工作正常。但如果 MySQL 要将这些字节理解为 Unicode 字符，则表字符集确实需要为 utf8(或 utf8mb4)。