E8919BF3A08481

mysql80 26> SELECT x'E8919BF3A08481', LENGTH(x'E8919BF3A08481'), CHARACTER_LENGTH(x'E8919BF3A08481');
+-------------------+---------------------------+-------------------------------------+
| x'E8919BF3A08481' | LENGTH(x'E8919BF3A08481') | CHARACTER_LENGTH(x'E8919BF3A08481') |
+-------------------+---------------------------+-------------------------------------+
| 葛󠄁                |                         7 |                                   7 |
+-------------------+---------------------------+-------------------------------------+
1 row in set (0.00 sec)

It seems that the correct result will be obtained if it is stored in the table.

mysql> SELECT version();
+-----------+
| version() |
+-----------+
| 8.0.27 |
+-----------+
1 row in set (0.00 sec)

mysql> CREATE TABLE ivs1(c VARCHAR(10)) COLLATE 'utf8mb4_bin';
Query OK, 0 rows affected (0.01 sec)

mysql> INSERT INTO ivs1 VALUES (x'E8919BF3A08481');
Query OK, 1 row affected (0.00 sec)

mysql> SELECT c, LENGTH(c), CHARACTER_LENGTH(c) FROM ivs1;
+---------+-----------+---------------------+
| c | LENGTH(c) | CHARACTER_LENGTH(c) |
+---------+-----------+---------------------+
| 葛? | 7 | 2 |
+---------+-----------+---------------------+
1 row in set (0.00 sec)

@nori-shinoda Wow, thank you!!

mysql80 8> SELECT x'E8919BF3A08481', LENGTH(x'E8919BF3A08481'), CHARACTER_LENGTH(x'E8919BF3A08481' COLLATE utf8mb4_bin), SUBSTR(x'E8919BF3A08481',
1, 2);
ERROR 1253 (42000): COLLATION 'utf8mb4_bin' is not valid for CHARACTER SET 'binary'

Treat it as varbinary ..

それはそうとして CHAR_LENGTH が2はなんかアレなので一応

https://bugs.mysql.com/bug.php?id=105904